Measurements (in mm). Body length: 2.00 (R. florum) – 9.00 (R. asellus). The widest point of the body (metathorax) measures up to 2.35 (R. vestita). Head width: 0.46 (R. florum) – 1.05 (R. vestita).

General. Body elongate, slender, curved, and usually rounded in cross section. All thoracic segments almost equal in size, or pronotum smaller than the next segments. Meso- and metathorax each divided dorsally into two folds, the prodorsum distinctly smaller than postdorsum or even vestigial. The pedal fold of thoracic segments very distinct, usually conical, and prominent. Abdominal segments I–VI of similar size, next segments tapering towards the posterior body end. Abdominal segments I–VII each divided dorsally into two transverse folds: prodorsum slightly smaller than postdorsum; postdorsum usually higher than prodorsum or in the form of conical protuberances; seldom both folds equally raised. Segments VIII and IX dorsally undivided. Epipleural fold of segments I–VIII conical. Laterosternal and eusternal folds of segments I–VIII conical, usually weakly distinct. Thoracic and abdominal cuticle densely covered with fine, unicoloured cuticular asperities. Abdominal segment X divided into four folds of equal size; almost completely hidden by the previous segment. Anus situated ventrally.

Thoracic spiracles often unicameral, but sometimes bicameral (R. antirrhini, R. florum, and R. melas), abdominal spiracles always unicameral; thoracic spiracles placed laterally on prothorax, close to mesothorax; abdominal spiracles placed antero-laterally or antero-medially on segments I–VIII.

Colouration. Head capsule light yellow to dark brown, medial parts of epicranium usually less sclerotised. All thoracic and abdominal segments whitish or light yellow. Pronotal sclerite indistinct, not more pigmented than the rest of the segment (only in R. eversmanni and R. neta slightly more pigmented than the rest of the segment).

Vestiture. Setae on body thin, yellowish, different in length (very short or medium), transparent or brownish.

Head capsule. Head suboval or slightly narrowed bilaterally, endocarinal line present, reaching from 1/2 to 4/5 of the length of frons. Frontal sutures usually very wide, hardly or weakly distinct. Frons covered with knobby asperities (R. collina, R. eversmanni, R. incana, and R. neta) or smooth. Usually only one single pair of anterior stemmata present, in the form of small black spots (st) close to the end of the frontal suture, two pairs of stemmata present in R. asellus, R. collina, R. incana, and R. linariae. Des₁ usually short or absent; des₂ usually elongated, located on the lateral part of the epicranium; long des₃ located anteriorly on the epicranium on the border of the frontal suture; des₄ minute or absent; and des₅ long, located anterolaterally. Fs_1-3 minute or absent, located medially; fs₄ long, located anteriorly; and long fs₅ located anterolaterally, close to the antenna. Les₁ and les₂ medium to short; single ves short or absent. One to five minute postepicranial setae (pes).

Antennae placed distally of the frontal suture, on the inside. Membranous and distinctly convex basal article bearing one conical sensorium plus some smaller sensilla: ampullacea, basiconica, or styloconica.

Clypeus trapezoidal, usually with two cls short to relatively elongated; sometimes basal part much more sclerotised than the apical parts; anterior border more or less curved towards the inside.

Mouth parts. Labrum usually distinct from clypeus by clypeo-labral suture (in R. pilosa, R. rara, and R. linariae clypeus and labrum fused) with three piliform lrs (only in R. linariae single lrs), usually lrs₁ and lrs₂ elongated, located medially, and lrs₃ short, located laterally; anterior border of labrum bi-sinuate or slightly rounded. Epipharynx mostly with two (rarely three) relatively elongated, finger-like als (almost identical in length); two or three piliform ams varying in size; without or with up to two short, finger-like mes; labral rods (lr) usually prominent, elongated, kidney-shaped, or rounded, almost indistinct. Mandibles apically bifid, cutting edge with additional protuberance or smooth; two medium-sized piliform mds, both located close to the lateral border. Maxillolabial complex: maxilla usually more sclerotised than labium, stipes with one stps, two pfs, and one mbs; stps and both pfs_1–2 short to elongated; mala with four to six finger-like dms variable in length; from two up to four piliform vms, medium to short in length. Maxillary palpi two-segmented; basal palpomere usually distinctly wider than distal one; length ratio of the basal and distal palpomeres usually almost 1:1; basal palpomere with short mpxs and two sensilla, distal palpomere with a group of two to six apical sensilla in the terminal receptive area. Prementum close to oval-shaped, with one medium prms (only R. herbarum with two prms); ligula with round or sinuate margin and one to three ligs; premental sclerite sclerotised in cup or ring form, sometimes incomplete, only in R. linariae indistinguishable, posterior extension absent or elongated; anterior median extension absent. Labial palpi one-segmented (in R. linariae labial palpi vestigial and almost invisible); each palp with a single pore, and a group of one to four apical sensilla (ampullacea) in the terminal receptive area; the surface of the labium smooth. Postmentum with two or three pms; membranous area smooth or partially covered with sharp or knobby asperities.

Thorax. Prothorax with four to 12 prns; two ps; and usually a short, single eus. Mesothorax with a single minute prs or without; three to four pds (variable in length) (only in R. linariae one pds and in R. pilosa two pds); one medium as (only R. rara without); three medium to minute ss; one medium eps; one or two medium ps; and a single minute eus (sometimes absent). Chaetotaxy of metathorax almost identical to that of mesothorax. Each pedal area of thoracic segments with three to six pda.

Abdomen. Segments I–VIII usually with one minute prs (sometimes absent on segment VIII, only R. bipustulata with two prs) and one to four pds; usually one minute and one medium ss; one to three eps; one ps; one minute lsts; and usually two minute eus. Abdominal segment IX without or with up to three minute ds; without or with up to two minute ps; and without or with up to two minute sts. Abdominal segment X mostly without seta.

Measurements (in mm). Body length: 1.86 (R. florum) – 6.50 (R. vestita). Body width: 1.66–3.50. Thorax width: 1.00–2.00.

Body. Integument white, sometimes with some parts dark and sclerotised; setae sometimes placed on pigmented spots, more or less stout, curved. Head with a pair of protuberances (h–pr) above eyes. Rostrum moderately elongated, in males usually as long as in females or only slightly shorter than in females, reaching mesocoxae (only in R. asellus rostrum very elongated, distinctly variable in both sexes, much longer in females). Pronotum trapezoidal. Pronotal protuberances (p–pr) separated at bases, wider than tall (conical in R. asellus), sometimes vestigial (R. linariae) or even absent (R. herbarum, R. pilosa, and R. rara). Meso- and metanotum similar in size. Abdominal segments I–VI almost identical in size; segment VII semicircular; segment VIII narrow, small; segment IX reduced. Abdominal protuberance (a–pr) on abdominal segment VIII usually visible, flattened or rounded, sometimes vestigial (R. linariae) or even absent (R. collina, R. eversmanni, R. pilosa, and R. rara). Urogomphi (ur) short, often ending in sclerotised, sharp apexes, sometimes vestigial or completely absent.

Chaetotaxy well developed, setae short to elongated, transparent or brownish. Head without or with one os, without or with one sos; rostrum without or with one pas, without or with up to two rs, without or with one es. Pronotum with one to three as, without or with up to four ls, two to four pls; without or with one ds. Dorsal parts of meso- and metathorax with two or three setae placed medially. Apex of femora usually with a single long fes, with two fes in R. asellus, R. tetra and R. bipustulata. Abdominal segments I–VII with two or up to six setae dorsally (segment VIII usually with fewer setae); one or two setae laterally, and two or up to five setae ventrally. Abdominal segment IX with two or up to four setae ventrally.

16 mature larvae; 4 ♂ pupae and 1 ♀ pupa. Serbia, Pirot, 700 m a.s.l., ex Verbascum thapsus L., 06.03.2017, leg., det. I. Toševski.

(Figs 1A, B, 2A–E, 3A–C). Measurements (in mm). Body length: 5.72–9.00 (avg. 7.55). The widest place in the body (meso- and metathorax) measures up to 2.40. Head width: 0.80–1.00 (avg. 0.85).

General. Body elongate, moderately slender, curved, rounded in cross section (Fig. 1A). Prothorax small, pronotal shield not pigmented. Mesothorax slightly smaller than metathorax; each divided dorsally into two folds (prodorsal fold smaller than postdorsal fold). Pedal folds of thoracic segments isolated, conical, prominent. Abdominal segments I–III of similar size, next segments tapering towards posterior body end. Abdominal segments I–VII each divided dorsally into two folds; postdorsal folds distinctly higher than prodorsal. Segments VIII and IX dorsally undivided. Epipleural folds of segments I–VII slightly conical. Laterosternal and eusternal folds of segments I–VII conical, weakly isolated. Abdominal segment X divided into four folds of equal size. Anus situated ventrally.

Figure 1. 

Rhinusa asellus (Gravenhorst, 1807) mature larva A habitus B head, frontal view.

All spiracles unicameral; thoracic spiracles placed laterally close to mesothorax; abdominal spiracles (Fig. 1A) placed mediolaterally on segments I–VIII.

Colouration. Yellow to brownish head, medial parts of epicranium less sclerotised (Fig. 1B). All thoracic and abdominal segments white (Fig. 1A). Cuticle covered with fine asperities.

Vestiture. Setae on body thin, yellowish, different in length (very short or medium).

Head capsule (Figs 1B, 2A). Head rather wide, endocarinal line present, reaching to 1/2 of the length of frons. Frontal sutures on head wide, unclear. Two pairs of stemmata (st): first in the form of a prominent pigmented spot with a convex cornea, close to the end of the frontal suture, second pair small, placed laterally, above the anterior stemma. Des₁ short, located in the central part of epicranium; long des₂ placed mediolaterally; long des₃ located anteriorly on epicranium close to the border with the frontal suture; des₄ short; long des₅ located anterolaterally above stemma (Fig. 2A). Fs₁ absent; fs₂ short; fs₃ absent; fs₄ long, located anteriorly; and long fs₅ located anterolaterally, close to antenna (Fig. 2A). Les₁ and les₂ medium, and one short ves. Epicranial area with four pes.

Figure 2. 

Rhinusa asellus (Gravenhorst, 1807) mature larva, head and mouth parts A head B antenna C clypeus and labrum (left side), epipharynx (right side) D left mandible E maxillolabial complex (schemes). Abbreviations: at–antenna, lr–labral rods, st–sensillum styloconicum, sb–sensillum basiconicum, Se–sensorium, st–stemmata, setae: als–anterolateral, ams–anteromedial, cls–clypeal, des–dorsal epicranial, dms–dorsal malar, fs–frontal epicranial, les–lateral epicranial, ligs–ligular, lrs–labral, mbs–malar basiventral, mds–mandibular dorsal, mes–medial, mpxs–maxillary palp, pes–postepicranial, pfs–palpiferal, pms–postmental, prms–premental, stps–stipital, ves–ventral, vms–ventral malar.

Antennae placed distally of the frontal suture, on the inside; membranous and distinctly convex basal article bearing one conical sensorium, relatively short, plus four sensilla differing in type: two basiconica and two styloconica (Fig. 2B).

Clypeus (Fig. 2C) ~ 3 × as wide as long with two medium cls, localised posterolaterally, with one sensillum between them; basal part distinctly sclerotised; anterior border straight.

Mouth parts. Labrum (Fig. 2C) trapezoidal, ~ 2.2 × as wide as long, with three piliform lrs, different in length; lrs₁ elongated, located medially, lrs₂ elongated, located posteromedially, and lrs₃ short, located anterolaterally; anterior border bi-sinuate. Epipharynx (Fig. 2C) with three medium finger-like als, almost identical in length; two medium piliform ams; and single medium finger-like mes; labral rods (lr) distinct, kidney shaped. Mandibles (Fig. 2D) bifid, cutting edge with additional protuberance; two medium piliform mds, both located in shallow pits, close to lateral border. Maxillolabial complex: maxilla (Fig. 2E) stipes with one stps, two pfs and one very short mbs and one sensillum, stps and both pfs_1–2 relatively long; mala with six finger-like dms variable in length; four piliform vms, medium to short in length. Maxillary palpi two-segmented; basal palpomere distinctly wider than distal one; length ratio of basal and distal palpomeres almost 1:1; basal palpomere with short mpxs and one sensillum, distal palpomere with a group of four apical sensilla in terminal receptive area. Prementum (Fig. 2E) oval-shaped, with one long prms; ligula with round margin and three short ligs; premental sclerite broad, sclerotised, cup-shaped, posterior extension medium in length, with thick apex. Labial palpi one-segmented; palpi with a single pore, and a group of four apical sensilla (ampullacea) on terminal receptive area; surface of labium smooth. Postmentum (Fig. 2E) with three pms, medium pms₁ located posterolaterally, elongated pms₂ located mediolaterally, and medium pms₃ located anterolaterally; posterior part of membranous area covered with knobby asperities.

Thorax. Prothorax (Fig. 3A) with nine medium prns, dorsal sclerite weakly visible; two medium ps; and single short eus. Mesothorax (Fig. 3A) with one short prs, one short and two medium pds; one medium as; three minute and one medium ss; one medium eps; one medium ps; and single short eus. Chae­totaxy of metathorax (Fig. 3A) almost identical to that of mesothorax. Each pedal area of thoracic segments with three long and two short pda.

Figure 3. 

Rhinusa asellus (Gravenhorst, 1807) mature larva, habitus A lateral view of thoracic segments B lateral view of abdominal segment I C lateral view of abdominal segments VII–X (schemes). Abbreviations: Th. 1–3–number of thoracic segments, Abd. 1–10–number of abdominal seg, setae: as–alar, ds–dorsal, eps–epipleural, eus–eusternal, lsts–laterosternal, pda–pedal, pds–postdorsal, prns–pronotal, prs–prodorsal, ss–spiracular, ps–pleural, sts–sternal.

Abdomen. Segments I–VII (Fig. 3B, C) with one very short prs; two short and one medium pds; one minute and one medium ss; one medium eps; one medium ps; one short lsts; and two short eus. Segment VIII (Fig. 3B, C) with two medium and one short pds; one medium ss; one medium eps; one medium ps; and two short eus. Abdominal segment IX (Fig. 3C) with one minute ps and one minute sts.

(Figs 4A–C, 5A–C). Measurements (in mm). Body length: 4.50–6.00; body width: 2.75–3.15; thorax width: 1.75–2.90; rostrum length: up to 1.60 ♂ and 2.60 ♀.

Figure 4. 

Rhinusa asellus (Gravenhorst, 1807) pupa habitus A ventral view B lateral view C dorsal view.

Figure 5. 

Rhinusa asellus (Gravenhorst, 1807) pupa habitus A ventral view B dorsal view C lateral view (schemes). Abbreviations: a–pr–abdominal protuberances, h–pr–head protuberances, p–pr–pronotal protuberances, ur–urogomphi, setae: as–apical, cs–coxal, d–dorsal, ds–discal, es–epistomal, fes–femoral, l, ls–lateral, os–orbital, pas–postantennal, pls–posterolateral, rs–rostral, sos–supraorbital, v–ventral.

Body. Integument brownish; moderately stout, curved. Elongated head protuberances present (h–pr) on head above eyes. Rostrum very elongate, in male almost 4 × as long as wide and reaching metacoxae; in female 7 × as long as wide and protruding past metacoxae. Pronotum trapezoidal, 1.5 × as wide as long. Pronotal protuberances (p–pr) well developed, conical, sclerotised, fused at base. Mesonotum slightly smaller than metanotum. Abdominal segments I–VI almost identical in size; segment VII semicircular; segment VIII narrow; segment IX reduced. Abdominal segment VIII dorsally with rounded, prominent, sclerotised abdominal protuberance (a–pr). Urogomphi (ur) vestigial, in the form of very short sclerotised, sharp protuberances. (Fig. 5C).

Chaetotaxy. Well developed, setae medium to elongated, transparent. Head with one very short sos, one medium os, and one medium-sized pas. Rostrum with two rs and one minute es (Fig. 5A). Pronotum with two as, one ds, two ls, and four pls almost equal in length; ds located in shallow pits. Dorsal parts of meso- and metathorax with three setae of various lengths, placed medially. Apex of femora with two long fes (Fig. 5A–C). Procoxae with a single seta (cs). Abdominal segments I–VII with six setae dorsally, variable in length: first minute, placed anteromedially; second and fourth minute; third and fifth medium, placed close to posterior margin of the segment; six, medium, placed below stigma (on segments VI and VII all setae medium). Abdominal segment VIII with four elongated setae dorsally. Each lateral part of abdominal segments I–VII with a single medium seta. Ventral parts of abdominal segments I–VIII with four setae, median pair longer than other ventral setae. Abdominal segment IX with four medium-sized setae ventrally (Fig. 5A–C).

This species is widely distributed in central and southern Europe, in the states of the Caucasus, and in western and central Turkey (Alonso-Zarazaga et al. 2023). Recently, it was reported as introduced into the USA (DiGirolomo et al. 2019). It is clearly related to R. tetra, from which the adult differs by the longer rostrum, especially in the female, the elongated shape of the elytra, and the male genitalia (Caldara 2014).

Larval hosts of R. asellus are restricted to species of Verbascum (V. nigrum L., V. phlomoides L., V. pulverulentum Vill., V. sinuatum L., V. thapsoides Schw., V. thapsus, and V. virgatum Stokes; Caldara 2014). The biology of this species was carefully studied by Gumovsky (2007). Adults can be found feeding on the shoots and leaves of the host plant beginning in May. Oviposition sites are typically concentrated in the top portion of the host plant. The female drills a hole in the host-plant tissues with her very long rostrum, and then she lays eggs there. Eggs develop in ~ 7 days. After hatching, the larva bores into the stem and feeds on plant tissues, often leading to swelling of the stem. Mature larvae form a pupal cell just beneath the outer layer of plant tissue within the stem. Larval and pupal development take on average 20 and 10 days, respectively. Sometimes R. asellus lives on the same host plant as R. tetra, although they occupy different niches.

21 mature larvae; 5 ♂ and 2 ♀ pupae. Italy, Lombardia, Linarolo (Pavia), ex Verbascum thapsus, 25.08.2015; 19 mature larvae; 7 premature; 3 ♂ and 4 ♀ pupae, Italy, Alto Adige, Castelrotto (Bolzano), ex Verbascum blattaria L., 10.08. 2017, all leg., det. R. Caldara.

(Figs 6A, B, 7A–E, 8A–C). Measurements (in mm). Body length: 3.25–6.50 (avg. 5.90). The widest place in the body (meso- and metathorax) measures up to 2.25. Head width: 0.85–0.90 (avg. 0.87).

Figure 6. 

Rhinusa tetra (Fabricius, 1792) mature larva A habitus B head, frontal view.

Figure 7. 

Rhinusa tetra (Fabricius, 1792) mature larva, head and mouth parts A head B antenna C clypeus and labrum (left side), epipharynx (right side) D left mandible E maxillolabial complex (schemes). Abbreviations: at–antenna, lr–labral rods, sb–sensillum basiconicum, Se–sensorium, st–stemmata, setae: als–anterolateral, ams–anteromedial, cls–clypeal, des–dorsal epicranial, dms–dorsal malar, fs–frontal epicranial, les–lateral epicranial, ligs–ligular, lrs–labral, mbs–malar basiventral, mds–mandibular dorsal, mes–medial, mpxs–maxillary palp, pes–postepicranial, pfs–palpiferal, pms–postmental, prms–premental, stps–stipital, ves–ventral, vms–ventral malar.

Figure 8. 

Rhinusa tetra (Fabricius, 1792) mature larva, habitus A lateral view of thoracic segments B lateral view of abdominal segment I C lateral view of abdominal segments VII–X (schemes). Abbreviations: Th. 1–3–number of thoracic segments, Abd. 1–10–number of abdominal seg, setae: as–alar, ds–dorsal, eps–epipleural, eus–eusternal, lsts–laterosternal, pda–pedal, pds–postdorsal, prns–pronotal, prs–prodorsal, ss–spiracular, ps–pleural, sts–sternal.

General. Body elongate, slender, curved, rounded in cross section (Fig. 6A). Prothorax smaller than mesothorax. Metathorax as wide as mesothorax; each divided dorsally into two folds (prodorsal fold much smaller than postdorsal fold). Pedal folds of thoracic segments prominent, conical, well isolated. Abdominal segments I–V of similar size, next segments tapering towards posterior body end. Abdominal segments I–VI each divided dorsally into two folds almost identical in size. Segments VII–IX dorsally undivided. Epipleural folds of segments I–VIII conical, well developed. Laterosternal and eusternal folds of segments I–VIII conical, well isolated. Abdominal segment X divided into four folds of equal size. Anus situated ventrally, almost completely hidden in segment IX.

Thoracic and abdominal spiracles unicameral; thoracic spiracles (Fig. 6A) placed laterally close to mesothorax; abdominal spiracles (Fig. 6A) placed medially on segments I–VIII.

Colouration. Light yellow to brownish head (Fig. 6B). All thoracic and abdominal segments whitish (Fig. 6A). Cuticle densely covered with fine asperities.

Vestiture. Setae on body thin, hair-like, different in length (minute to medium).

Head capsule (Figs 6B, 7A). Head wide, endocarinal line present, reaching to 1/2 of the length of frons. Frontal sutures on head wide, indistinct. A single pair of stemmata in the form of small black spots (st) placed laterally, close to the end of the frontal suture. Des₁ very short, located in middle part of epicranium; very long des₂ located anteriorly; very long des₃ placed almost on the border of the frontal suture; very short des₄, located laterally; and long des₅ placed anterolaterally above stemma (Fig. 7A). Fs₁ and fs₂ minute, located posterolaterally; fs₃ absent; fs₄ medium, located anteriorly; and long fs₅ located anterolaterally, close to antenna (Fig. 7A). Les₁ and les₂ medium; single short ves. Epicranial area with four pes.

Antennae placed distally of the frontal suture, on the inside; membranous and distinctly convex basal article bearing one conical, moderately elongate sensorium, plus two sensilla basiconica (Fig. 7B).

Clypeus (Fig. 7C) trapezoidal, ~ 2.5 × as wide as long with two relatively long cls, localised posterolaterally, with one sensillum between them; anterior border almost straight.

Mouth parts. Labrum (Fig. 7C) ~ 2.2 × as wide as long, with three piliform lrs, various long; lrs₁ elongated, located posteromedially, on small protuberance, lrs₂ medium, located lateromedially, and lrs₃ short, located laterally; anterior border almost straight. Epipharynx (Fig. 7C) with two elongated finger-like als identical in length, three piliform ams variable in length, and two short, finger-like mes; labral rods (lr) distinct, kidney-shaped. Mandibles (Fig. 7D) bifid, cutting edge straight; two medium piliform and short mds, both located close to lateral border. Maxillolabial complex: maxilla brownish sclerotised (Fig. 7E) stipes with one stps, two pfs and one short mbs, stps and both pfs_1–2 elongated; mala with six finger-like dms variable in length; four medium piliform vms. Maxillary palpi two-segmented; basal palpomere distinctly wider than distal one; both palpomeres equal in length; basal palpomere with short mpxs and two sensilla, distal palpomere with a group of six apical sensilla in terminal receptive area. Prementum (Fig. 7E) close to oval-shaped, with a single elongated prms; ligula with rounded margin and two, short ligs; premental sclerite broad, sclerotised, cup-shaped, posterior extension short with thick apex. Labial palpi one-segmented; palpi with a single pore, and four apical sensilla in terminal receptive area; surface of labium smooth. Postmentum (Fig. 7E) with three pms, medium pms₁ located posteromedially, long pms₂ located mediolaterally, and elongated pms₃ located anterolaterally; membranous area partially covered with knobby asperities.

Thorax. Prothorax (Fig. 8A) with eight elongated and single medium prns; two elongated ps; and single short eus. Mesothorax (Fig. 8A) with a single short prs; two medium and one short pds (ordered: medium, medium, short); one short as; two medium and one short ss; one medium eps; one medium ps; and single minute eus. Chaetotaxy of metathorax (Fig. 8A) almost identical to that of mesothorax. Each pedal area of thoracic segments with five elongated and one short pda.

Abdomen. Segments I–VIII (Fig. 8B, C) with one very short prs (segment VIII without prs), three pds of various length; one medium and one long ss; single elongated eps; one medium ps; one short lsts; and two minute eus. Abdominal segment IX (Fig. 8C) with one short and two minute ds; two minute ps; and two minute sts.

(Figs 9A–C, 10A–C). Measurements (in mm). Body length: 3.75–5.25; body width: 2.40–2.75; thorax width: 1.05–1.75; rostrum length: up to 0.70 ♂ and ♀.

Figure 9. 

Rhinusa tetra (Fabricius, 1792) pupa habitus A ventral view B lateral view C dorsal view.

Figure 10. 

Rhinusa tetra (Fabricius, 1792) pupa habitus A ventral view B dorsal view C lateral view (schemes). Abbreviations: a–pr–abdominal protuberances, h–pr–head protuberances, p–pr–pronotal protuberances, ur–urogomphi, setae: as–apical, d–dorsal, ds–discal, fes–femoral, l, ls–lateral, os–orbital, pls–posterolateral, sos–supraorbital, rs–rostral, v–ventral.

Body. Integument white, with some parts dark sclerotised; moderately elongated. Elongated head protuberances (h–pr) present on head above eyes. Rostrum moderately elongated, on both sexes almost 2.8 × as long as wide and protruding mesocoxae. Pronotum trapezoidal 2 × as wide as long. Pronotal protuberances (p–pr) flattened, sclerotised, separated at bases. Mesonotum slightly narrower than metanotum. Abdominal segments I–VI almost identical in size, VII semicircular, segment VIII narrow, segment IX reduced. Abdominal segment VIII dorsally with rounded, well developed abdominal protuberance (a–pr). Urogomphi (ur) very short, ending with sclerotised, sharp apexes (Fig. 9A–C).

Chaetotaxy. Well developed, setae medium to short. Head with one medium sos and one medium os. Rostrum with a single rs (Fig. 10A). Pronotum with two as, two ls, single ds, and four pls, all equal in length. Dorsal parts of meso- and metathorax with three setae of various length, placed medially. Apex of femora with two long fes (Fig. 10A–C). Abdominal segments I–VII dorsally with five setae dorsally, variable in length: first, second and fourth minute, third and fifth medium; first seta placed posteromedially, second to fourth placed close to posterior margin of the segment, fifth placed below stigma. Segment VII with four elongated setae dorsally, segment VIII with three elongated setae dorsally. Each lateral part of abdominal segments I–VIII with a single short seta. Ventral parts of abdominal segments I–VIII with four setae (first distinctly longer than other setae). Abdominal segment IX with three short setae ventrally (Fig. 10A–C).

This species is one of the most common and widespread of the genus Rhinusa. It has been reported in all of Europe, Siberia, North Africa, the Middle East, central Asia, and northern India. It was accidentally introduced in North America, where it is currently distributed in several states of the USA and Canada (O’Brien and Wibmer 1982; DiGirolomo et al. 2019). Although it was proposed as a potential candidate for the biological control of invasive common mullein, Verbascum thapsus, it was not used in North America in this regard. In the southern part of its area of distribution, it can be confused with other species of the group, such as R. verbasci (Rosenschoeld, 1838), R. moroderi (Reitter, 1906), and R. weilli Caldara, 2014, from which it can be separated only by the shape of the female rostrum, most easily if observed in lateral view (Caldara 2014). It is well known that adults of R. tetra are highly variable in size (2.0–4.5 mm), even among specimens collected from the same plant. Additionally, the rostrum length of the female distinctly varies among populations living on different plants, probably related to oviposition inside seed capsules of different sizes and thicknesses, as suggested to occur in R. dieckmanni (Behne, 1988) (Toševski et al. 2023).

This species was reported to feed on several species of Verbascum. Caldara et al. (2012) verified the following plant associations: Verbascum blattaria, V. boerhavii L., V. creticum (L.) Cav., V. lychnitis L., V. nigrum, V. phlomoides, V. phoeniceum L., V. pulverulentum, V. speciosum Schrader, V. thapsiforme Schrader, and V. thapsus. Adults were also collected on Scrophularia auriculata L., S. canina L., and S. laevigata Vahl.

Marquess (2000) provides very detailed information on the biology of this species. Adults feed on the dorsal surfaces of leaves and on the seed capsules of the host plant. Once a plant flowers, mating occurs on the entire inflorescence. The female usually oviposits 1–3 eggs per seed capsule. Egg hatching occurs 7–11 days after deposition. Larvae feed on seeds within capsules and consume the majority of them. Pupation occurs within the seed capsule, and the emergence of the adults occurs ~ 25 days later. Adults exit the seed capsule by chewing through the hardened pericarp.

29 mature larvae; 28 ♂ and 26 ♀ pupae. Serbia, Zemun, ex Linaria vulgaris Mill., 15.08.2017, leg., det. I. Toševski.

(Figs 11A, B, 12A–E, 13A–C). Measurements (in mm). Body length: 3.00–4.25 (avg. 3.60). The widest place in the body (meso- and metathorax) measures up to 1.25. Head width: 0.55–0.60 (avg. 0.56).

Figure 11. 

Rhinusa antirrhini (Paykull, 1800) mature larva A habitus B head, frontal view.

Figure 12. 

Rhinusa antirrhini (Paykull, 1800) mature larva, head and mouth parts A head B antenna C clypeus and labrum (left side), epipharynx (right side) D left mandible E maxillolabial complex (schemes). Abbreviations: at–antenna, lr–labral rods, sa–sensillum ampullaceum, sb–sensillum basiconicum, Se–sensorium, st–stemmata, setae: als–anterolateral, ams–anteromedial, cls–clypeal, des–dorsal epicranial, dms–dorsal malar, fs–frontal epicranial, les–lateral epicranial, ligs–ligular, lrs–labral, mbs–malar basiventral, mds–mandibular dorsal, mes–medial, mpxs–maxillary palp, pes–postepicranial, pfs–palpiferal, pms–postmental, prms–premental, stps–stipital, ves–ventral, vms–ventral malar.

Figure 13. 

Rhinusa antirrhini (Paykull, 1800) mature larva, habitus A lateral view of thoracic segments B lateral view of abdominal segment I C lateral view of abdominal segments VII–X (schemes). Abbreviations: Th. 1–3–number of thoracic segments, Abd. 1–10–number of abdominal seg, setae: as–alar, ds–dorsal, eps–epipleural, eus–eusternal, lsts–laterosternal, pda–pedal, pds–postdorsal, prns–pronotal, prs–prodorsal, ss–spiracular, ps–pleural, sts–sternal.

General. Body elongate, slender, distinctly curved, rounded in cross section (Fig. 11A). All thoracic segments almost equal in size. Meso- and metathorax each divided dorsally into two folds (prodorsal fold distinctly smaller than postdorsal fold). Pedal folds of thoracic segments isolated, conical, prominent. Abdominal segments I–VI of similar size, next segments tapering towards posterior body end. Abdominal segments I–VII each divided dorsally into two folds: prodorsal fold slightly smaller than postdorsal; both folds equally in high. Segments VIII and IX dorsally undivided. Epipleural folds of segments I–VIII conical. Laterosternal and eusternal folds of segments I–VIII conical, weakly isolated. Abdominal segment X (almost completely hidden in previous segment) divided into four folds of equal size. Anus situated ventrally.

Thoracic spiracles bicameral, abdominal unicameral; thoracic spiracles (Fig. 11A) placed laterally close to mesothorax; abdominal spiracles (Fig. 11A) placed antero-laterally on segments I–VIII.

Colouration. All thoracic and abdominal segments whitish (Fig. 11A). Cuticle densely covered with fine asperities. Dark yellow to dark brown head, medial parts of epicranium less sclerotised (Fig. 11B).

Vestiture. Setae on body thin, yellowish, different in length (very short or medium).

Head capsule (Figs 11B, 12A). Head slightly narrowed bilaterally, endocarinal line present, reaching to the 2/3 of the length of frons. Frontal sutures on head very wide, indistinct. Single pair of stemmata in the form of small black spots (st) close to the end of the frontal suture. Des₁ absent; des₂ short, located in lateral part of epicranium; long des₃ located anteriorly on epicranium on border of the frontal suture; des₄ minute; and des₅ long, located anterolaterally above stemma (Fig. 12A). Fs₁ absent; fs₂ short, located medially; fs₃ absent; fs₄ long, located anteriorly; and long fs₅ located anterolaterally, close to antenna (Fig. 12A). Les₁ short and medium les₂; two short ves. Epicranial area with three pes.

Antennae placed distally of the frontal suture, on the inside; membranous and distinctly convex basal article bearing one conical sensorium, plus four sensilla ampullacea and single sensillum basiconicum (Fig. 12B).

Clypeus (Fig. 12C) trapezoidal, ~ 3.2 × as wide as long with two short cls, localised posterolaterally, with one sensillum between them; except the posterior part, whole clypeus darkly sclerotised; anterior border slightly curved towards the inside.

Mouth parts. Labrum (Fig. 12C) ~ 2.2 × as wide as long, with three piliform lrs, various long; lrs₁ and lrs₂ elongated, located medially, and lrs₃ short, located laterally; anterior border bi-sinuate. Epipharynx (Fig. 12C) with two relatively elongated finger-like als, almost identical in length; three ams various in size; and single short finger-like mes; labral rods (lr) distinct, rounded. Mandibles (Fig. 12D) bifid, cutting edge with additional protuberance; two medium piliform mds, both located close to lateral border. Maxillolabial complex: maxilla more sclerotised than labium (Fig. 12E) stipes with one stps, two pfs and one short mbs, stps, and both pfs_1–2 medium; mala with five finger-like dms variable in length; four piliform vms, medium to short in length. Maxillary palpi two-segmented; basal palpomere distinctly wider than distal one; length ratio of basal and distal palpomeres almost 1:1; basal palpomere with short mpxs and two sensilla, distal palpomere with a group of two or three apical sensilla in terminal receptive area. Prementum (Fig. 12E) close to oval-shaped, with one medium prms; ligula with round margin and two short ligs; premental sclerite vestigial, only lateral parts dark sclerotised. Labial palpi one-segmented; each palp with a single pore, and a group of one or two apical sensilla (ampullacea) on terminal receptive area; surface of labium smooth. Postmentum (Fig. 12E) with three pms, elongated pms₁ located medially, long pms₂ located laterally, and medium pms₃ located antero-laterally; membranous area smooth.

Thorax. Prothorax (Fig. 13A) with ten relatively long prns; two medium ps; and single short eus. Mesothorax (Fig. 13A) without prs; one minute and two medium pds; one medium as; three medium ss; one medium eps; one medium ps; and single minute eus. Chaetotaxy of metathorax (Fig. 13A) almost identical to that of mesothorax. Each pedal area of thoracic segments with three medium and three minute pda.

Abdomen. Segments I–VIII (Fig. 13B, C) with one minute prs (segment VIII without); one minute and two medium pds; one minute and one medium ss; two medium eps; one minute ps; one minute lsts; and two minute eus. Abdominal segment IX (Fig. 13C) with two minute ds; two minute ps; and two minute sts.

(Figs 14A–C, 15A–C). Measurements (in mm). Body length: 2.35–3.30 (avg. 2.75); body width: 1.45–1.85 (avg. 1.60); thorax width: 0.90–1.20 (avg. 1.05); rostrum length: up to 0.60 ♂ and 0.75 ♀.

Figure 14. 

Rhinusa antirrhini (Paykull, 1800) pupa habitus A ventral view B lateral view C dorsal view.

Figure 15. 

Rhinusa antirrhini (Paykull, 1800) pupa habitus A ventral view B dorsal view C lateral view (schemes). Abbreviations: a–pr–abdominal protuberances, h–pr–head protuberances, p–pr–pronotal protuberances, ur–urogomphi, setae: as–apical, d–dorsal, fes–femoral, l, ls–lateral, os–orbital, pls–posterolateral, v–ventral.

Body. Integument white, with some parts dark sclerotised; moderately stout, curved (Fig. 14A–C). All pronotal setae placed on pigmented spots. Head with a pair of distinct head protuberances (h–pr) above eyes. Rostrum rather short, in male usually only slightly shorter than in female: almost 3 × as long as wide, reaching mesocoxae. Pronotum trapezoidal 2 × as wide as long. Pronotal protuberances (p–pr) conical, flattened, sclerotised, separated at bases. Mesonotum and metanotum similar in size. Abdominal segments I–VI almost identical in size; segment VII semicircular; segment VIII narrow; segment IX reduced. Abdominal segment VIII dorsally with rounded, prominent, sclerotised abdominal protuberance (a–pr). Urogomphi (ur) short, ending with sclerotised, sharp apexes (Fig. 15A–C).

Chaetotaxy. Well developed, setae short to elongated, transparent. Head with one short os (Fig. 15A). Pronotum with two as, four ls, and three pls almost equally in length. Dorsal parts of meso- and metathorax with three setae of various length, placed medially. Apex of femora with a single long fes (Fig. 15A–C). Abdominal segments I–VII with five setae dorsally, variable in length: first and third minute, second, fourth and fifth medium; first to fourth placed close to posterior margin of the segment, fifth placed below stigma (on segments VI and VII all setae medium). Abdominal segment VIII with four elongated setae dorsally. Each lateral part of abdominal segments I–VII with two medium setae. Ventral parts of abdominal segments I–VIII with four medium-sized setae. Abdominal segment IX with two medium setae ventrally (Fig. 15A–C).

This species is reported from all of Europe, although it is probable that, especially in the Balkans, it is confused with several cryptic species still to be described on the basis of molecular studies (Hernández-Vera et al. 2010; IT, pers. obs.). Rhinusa antirrhini lives on Linaria spp. other than L. vulgaris. This weevil was accidentally imported into North America at the beginning of the twentieth century, where it became important in applied entomology when proposed for the biological control of the invasive plant species L. vulgaris (see Hernández-Vera et al. 2010 and DiGirolomo et al. 2019 for references). The adult is sometimes confused with R. dieckmanni, as recently shown by Toševski et al. (2023).

This univoltine weevil feeds on L. vulgaris and L. angustissima (Loisel.) Borbás, in the capsules of which larvae and pupae can be found. Adults emerge at the end of May, visiting flowers to start consuming pollen, and shortly after that, copulation begins. After mating, the females start laying eggs in well-developed floral ovaries, usually in their upper parts. When oviposition occurs, the outside of the seed capsule has a long, cone-shaped protrusion immediately above the oviposition site. This drives the formation of a semi-gall in that area. The early instar larvae feed primarily on hypertrophied seeds, while older and later instars consume abortive seeds. Most often, a single seed capsule contains one R. antirrhini larva, while at high densities, two larvae per capsule are commonly found. Development to adult takes ~ 30–50 days, depending on the environmental temperature. Newly emerged adults feed on young shoots of their host plant, expressing irregular aestivation periods until mid-autumn, when adults intensify feeding just before entering hibernation. Adults overwinter at the soil surface, sheltered below or between dry plant remains (IT, pers. obs.).

19 mature larvae; 20 ♂ and 6 ♀ pupae. Serbia, Vinci, ex Linaria genistifolia (L.) Miller, 05.06.2017, leg., det. I. Toševski.

(Figs 16A, B, 17A–E, 18A–C). Measurements (in mm). Body length: 2.00–3.50 (avg. 3.00). The widest place in the body (meso- and metathorax) measures up to 1.20. Head width: 0.46–0.54 (avg. 0.52).

Figure 16. 

Rhinusa florum (Rubsaamen, 1895) mature larva A habitus B head, frontal view.

Figure 17. 

Rhinusa florum (Rubsaamen, 1895) mature larva, head and mouth parts A head B antenna C clypeus and labrum (left side), epipharynx (right side) D left mandible E maxillolabial complex (schemes). Abbreviations: at–antenna, lr–labral rods, sb–sensillum basiconicum, Se–sensorium, st–stemmata, setae: als–anterolateral, ams–anteromedial, cls–clypeal, des–dorsal epicranial, dms–dorsal malar, fs–frontal epicranial, les–lateral epicranial, ligs–ligular, lrs–labral, mbs–malar basiventral, mds–mandibular dorsal, mes–medial, mpxs–maxillary palp, pes–postepicranial, pfs–palpiferal, pms–postmental, prms–premental, stps–stipital, ves–ventral, vms–ventral malar.

Figure 18. 

Rhinusa florum (Rubsaamen, 1895) mature larva, habitus A lateral view of thoracic segments B lateral view of abdominal segment I C lateral view of abdominal segments VII–X (schemes). Abbreviations: Th. 1–3–number of thoracic segments, Abd. 1–10–number of abdominal seg, setae: as–alar, ds–dorsal, eps–epipleural, eus–eusternal, lsts–laterosternal, pda–pedal, pds–postdorsal, prns–pronotal, prs–prodorsal, ss–spiracular, ps–pleural, sts–sternal.

General. Body elongate, slightly curved, oblate dorsoventrally in cross section (Fig. 16A). Prothorax prominent, pronotal shield not pigmented; meso-­ and metathorax equal in size, smaller than prothorax. Meso- and metathorax each divided dorsally into two folds (prodorsal fold distinctly smaller than postdorsal fold). Pedal folds of thoracic segments isolated, conical, prominent. Abdominal segments I–VI of similar size, next segments tapering towards posterior body end. Abdominal segments I–VII each divided dorsally into two almost equal in size folds; postdorsal folds only slightly higher than prodorsal folds. Segments VIII and IX dorsally undivided. Epipleural folds of segments I–VIII conical. Laterosternal and eusternal folds of segments I–VIII conical, weakly isolated. Abdominal segment X divided into four folds of equal size. Anus situated ventrally, almost completely covered with the ninth abdominal segment.

Thoracic spiracles bicameral, abdominal unicameral; thoracic spiracles (Fig. 16A) placed laterally close to mesothorax; abdominal spiracles (Fig. 16A) placed mediolaterally on segments I–VIII.

Colouration. Cuticle covered with fine asperities. Brown head, medial parts of epicranium less sclerotised (Fig. 16B). All thoracic and abdominal segments whitish (Fig. 16A).

Vestiture. Setae on body thin, yellowish, different in length (very short or medium).

Head capsule (Figs 16B, 17A). Head suboval, endocarinal line present, reaching to the 3/4 of the length of frons. Frontal sutures on head distinct, very wide. Single pair of stemmata in the form of small black spots (st) close to the end of the frontal suture. Des₁ short, located in middle part of epicranium; long des₂; long des₃ located anteriorly on epicranium close to the border with the frontal suture; des₄ absent; and des₅ long, located anterolaterally above stemma (Fig. 17A). Fs₁ and fs₂ short, located medially; fs₃ absent; long fs₄ located anteriorly; and long fs₅ located anterolaterally, close to antenna (Fig. 17A). Les₁ and les₂ medium; single medium ves. Epicranial area with five pes.

Antennae placed distally of the frontal suture, on the inside; membranous and distinctly convex basal article bearing one conical, slightly elongate sensorium, plus three sensilla basiconica (Fig. 17B).

Clypeus (Fig. 17C) trapezoidal, ~ 3.6 × as wide as long with two relatively long cls, localised posterolaterally, with one sensillum between them; basal part distinctly sclerotised; anterior border curved towards the inside.

Mouth parts. Labrum (Fig. 17C) ~ 3 × as wide as long, with three piliform lrs, variously long; lrs₁ and lrs₂ elongated, located medially, lrs₃ short, located anterolaterally; anterior border bi-sinuate. Epipharynx (Fig. 17C) with two relatively elongated finger-like als, almost identical in length; two piliform ams various in size; and single short finger-like mes; labral rods (lr) close to kidney-shaped. Mandibles (Fig. 17D) bifid, cutting edge straight; two medium piliform mds, both located in shallow pits, close to lateral border. Maxillolabial complex: maxilla dark sclerotised (Fig. 17E), stipes with one stps, two pfs, and one very short mbs and one sensillum, stps and both pfs_1–2 relatively long; mala with five finger-like dms variable in length (first and second much longer than others); five piliform vms, medium to short in length. Maxillary palpi two-segmented; basal palpomere distinctly wider than distal one; length ratio of basal and distal palpomeres almost 1:1; basal palpomere with short mpxs and two sensilla, distal palpomere with a group of six apical sensilla in terminal receptive area. Prementum (Fig. 17E) oval-shaped, with one long prms; ligula with round margin and three short ligs; premental sclerite vestigial, only basal part highly sclerotised. Labial palpi one-segmented; palpi with a single pore, and a group of five apical sensilla (ampullacea) on terminal receptive area; surface of labium smooth. Postmentum (Fig. 17E) with three pms, elongated pms₁ located medially, medium pms₂ located laterally, and relatively short pms₃ located antero-laterally; membranous area smooth.

Thorax. Prothorax (Fig. 18A) with 12 medium prns, dorsal sclerite weakly visible; two medium ps; and single short eus. Mesothorax (Fig. 18A) with one minute prs, two minute and one medium pds (ordered: minute, medium, minute); one medium as; three medium ss; one medium eps; one medium ps; and single minute eus. Chaetotaxy of metathorax (Fig. 18A) almost identical to that of mesothorax. Each pedal area of thoracic segments with four medium and one minute pda.

Abdomen. Segments I–VIII (Fig. 18B, C) with one minute prs (segment VIII without); one minute and one medium pds; one minute and one medium ss; two medium eps; one medium ps; one medium lsts; and two short eus. Abdominal segment IX (Fig. 18C) with one minute and medium ds; one medium ps; and two medium sts.

(Figs 19A–C, 20A–C). Measurements (in mm). Body length: 1.86–2.93 (avg. 2.60); body width: 1.66–1.86 (avg. 1.80); thorax width: 1.00–1.16 (avg. 1.06); rostrum length: up to 0.66 ♂ and 0.73 ♀.

Figure 19. 

Rhinusa florum (Rubsaamen, 1895) pupa habitus A ventral view B lateral view C dorsal view.

Figure 20. 

Rhinusa florum (Rubsaamen, 1895) pupa habitus A ventral view B dorsal view C lateral view (schemes). Abbreviations: a–pr–abdominal protuberances, h–pr–head protuberances, p–pr–pronotal protuberances, ur–urogomphi, setae: as–apical, d–dorsal, ds–discal, fes–femoral, l, ls–lateral, os–orbital, pls–posterolateral, rs–rostral, v–ventral.

Body. Integument white, with some parts dark sclerotised; moderately stout, curved. All setae placed on dark brown spots. Head protuberances (h–pr) present on head above eyes. Rostrum rather short, in male usually only slightly shorter than in female almost 2.3 × as long as wide, reaching mesocoxae. Pronotum trapezoidal 2.4 × as wide as long. Pronotal protuberances (p–pr) conical, sclerotised, separated at bases. Meso- and metanotum similar in size. Abdominal segments I–VI almost identical in size; segment VII semicircular; segment VIII narrow; segment IX reduced. Abdominal segment VIII dorsally with rounded, prominent, sclerotised abdominal protuberance (a–pr). Urogomphi (ur) medium, ending with sclerotised, sharp apexes (Fig. 19A–C).

Chaetotaxy. Well developed, setae medium to elongated, transparent. Head with one medium os. Rostrum with a single rs (Fig. 20A). Pronotum with two as, one ds, two ls, and four pls variable in length. Dorsal parts of meso- and metathorax with three setae of various length, placed medially. Apex of femora with a single long fes (Fig. 20A–C). Abdominal segments I–VII with six setae dorsally, variable in length: first minute, placed anteromedially; second and fourth minute; third and fifth medium, placed close to posterior margin of the segment; sixth medium, placed below stigma (on segments VI and VII all setae from second to sixth medium). Abdominal segment VIII with four elongated setae dorsally. Each lateral part of abdominal segments I–VII with two medium setae. Ventral parts of abdominal segments I–VIII with four medium setae. Abdominal segment IX with four medium setae ventrally (Fig. 20A–C).

This species is distributed in Central Europe, the Balkans, the Caucasus, and the Middle East (Alonso-Zarazaga et al. 2023). It is clearly distinguishable from R. antirrhini and the other species of this group by the shape of its rostrum, which in lateral view is almost straight and gradually narrowed from base to apex and not abruptly tapered at the antennal insertion.

Rhinusa florum is a univoltine weevil that inhabits lowlands, hilly slopes, and mountain meadows at elevations up to 2000 m. The host plants are Linaria genistifolia and L. dalmatica (L.) Mill. Adults emerge in early June following the occurrence of flowering. Copulation occurs shortly thereafter, with the egg-laying period lasting from mid-June until the end of July. Oviposition occurs on the widest part of the developing ovary. During oviposition, females secrete a fluid that fixes the egg to the ovule. Females lay one egg per ovary. Egg deposition triggers a strong proliferative tissue reaction manifested as a solid, conical gall formation that grows inside the flower lumen. The galled tissue is the only resource for larval development. Pupation takes place inside the gall, and adults emerge after approximately two weeks. The adults overwinter in soil and litter close to the host plants (IT, pers. obs.).

7 mature larvae; 7 ♂ and 12 ♀ pupae. Serbia, Didič, ex Linaria vulgaris galls, 05.07.2017, leg., det. I. Toševski.

(Figs 21A, B, 22A–E, 23A–C). Measurements (in mm). Body length: 2.33–4.30 (avg. 3.66). The widest place in the body (meso- and metathorax) measures up to 1.16. Head width: 0.46–0.53 (avg. 0.50).

Figure 21. 

Rhinusa linariae (Panzer, 1796) mature larva A habitus B head, frontal view.

Figure 22. 

Rhinusa linariae (Panzer, 1796) mature larva, head and mouth parts A head B antenna C clypeus and labrum (left side), epipharynx (right side) D left mandible E maxillolabial complex (schemes). Abbreviations: at–antenna, lr–labral rods, sa–sensillum ampullaceum, sb–sensillum basiconicum, Se–sensorium, st–stemmata, setae: als–anterolateral, ams–anteromedial, cls–clypeal, des–dorsal epicranial, dms–dorsal malar, fs–frontal epicranial, les–lateral epicranial, ligs–ligular, lrs–labral, mbs–malar basiventral, mds–mandibular dorsal, mpxs–maxillary palp, pes–postepicranial, pfs–palpiferal, pms–postmental, prms–premental,, stps–stipital, ves–ventral, vms–ventral malar.

Figure 23. 

Rhinusa linariae (Panzer, 1796) mature larva, habitus A lateral view of thoracic segments B lateral view of abdominal segment I C lateral view of abdominal segments VII–X (schemes). Abbreviations: Th. 1–3–number of thoracic segments, Abd. 1–10–number of abdominal seg, setae: as–alar, ds–dorsal, eus–eusternal, lsts–laterosternal, pda–pedal, pds–postdorsal, prns–pronotal, ss–spiracular, ps–pleural.

General. Body elongate, slender, strongly curved, rounded in cross section (Fig. 21A). All thoracic segments almost equal in size. Pronotal shield not pigmented. Meso- and metathorax each divided dorsally into two folds (prodorsal fold small, postdorsal prominent). Pedal folds of thoracic segments prominent, conical, and well isolated. Abdominal segments I–IV of similar size, as large as metathorax. Segments V–IX tapering towards posterior body end. Abdominal segments I–VI each divided dorsally into two variously sized folds: prodorsal small, postdorsal folds distinctly larger and much higher than prodorsal folds. Segments VII–IX dorsally undivided. Epipleural folds of segments I–VIII conical. Laterosternal and eusternal folds of segments I–VIII weakly isolated. Abdominal segment X divided into four folds of equal size. Anus situated ventrally, hidden inside ninth segment.

Thoracic and abdominal spiracles unicameral; thoracic spiracles (Figs 21A, 23A) placed laterally close to mesothorax; abdominal spiracles (Figs 21A, 23B, C) placed antero-laterally on segments I–VIII.

Colouration. Light yellow head (Fig. 21B). All thoracic and abdominal segments white (Fig. 21A). Cuticle covered with fine asperities.

Vestiture. Setae on body thin, transparent, different in length (very short or medium).

Head capsule (Figs 21B, 22A). Head suboval, endocarinal line present, reaching to 2/3 length of frons. Frontal sutures on head indistinct, very wide. Two pairs of stemmata in the form of small dark spots (st) placed mediolaterally. Des₁ short, located medially; des₂ long; long des₃ located anteriorly on border of the frontal suture; des₄ absent; and des₅ long, located anterolaterally (Fig. 22A). Fs₁ and fs₂ minute, located medially; fs₃ absent; fs₄ long, located anteriorly; and long fs₅ located anterolaterally, close to antenna (Fig. 22A). Les₁ and les₂ medium. Epicranial area with four pes.

Antennae placed distally of the frontal suture, on the inside; membranous and distinctly convex basal article bearing one conical elongate sensorium, plus three sensilla: two basiconica and single ampullacea (Fig. 22B).

Clypeus and labrum (Fig. 22C) completely fused, trapezoidal, 3 × as wide as long, with a single short cls, localised posterolaterally; one sensillum posteromedially and single medium piliform lrs, located medially; anterior border sinuate. Epipharynx (Fig. 22C) with two finger-like als and single piliform ams, all relatively elongated; labral rods (lr) rounded, placed close to the anterior border.

Mouth parts. Mandibles (Fig. 22D) bifid, cutting edge with small protuberance; two piliform various in size mds, both located, close to lateral border. Maxillolabial complex: maxilla dark sclerotised (Fig. 22E), stipes with one stps, two pfs, and one minute mbs, stps, and both pfs_1–2 relatively short; mala with four finger-like dms variable in length; three piliform vms, medium to short in length. Maxillary palpi two-segmented; basal palpomere distinctly wider than distal one; length ratio of basal and distal palpomeres almost 1:1; basal palpomere with short mpxs and single sensillum, distal palpomere with a group of five apical sensilla in terminal receptive area. Prementum (Fig. 22E) oval-shaped, with one medium prms; ligula with round margin and single medium ligs; premental sclerite undefined, weakly sclerotised, without posterior extension. Labial palpi one-segmented, vestigial, visible only under great magnification (40×). Each terminal receptive area with a single apical sensilla. Postmentum (Fig. 22E) with only two pms: pms₁ absent; medium pms₂ located mediolaterally, and relatively short pms₃ located anterolaterally; membranous area covered with knobby processes.

Thorax. Prothorax (Fig. 23A) with eigth medium prns, dorsal sclerite weakly visible; two medium ps; and single short eus. Mesothorax (Fig. 23A) with one medium pds; one medium as; two medium and single minute ss; and one short ps. Chaetotaxy of metathorax (Fig. 23A) almost identical to that of mesothorax. Each pedal area of thoracic segments with five various in size pda.

Abdomen. Segments I–VIII (Fig. 23B, C) with one medium pds; one medium ss; one short ps; one short lsts; and one short eus. Abdominal segment IX (Fig. 23C) with one medium ds and two short ps.

(Figs 24A–C, 25A–C). Measurements (in mm). Body length: 1.66–2.66 (avg. 2.10); body width: 1.40–1.93 (avg. 1.60); thorax width: 0.90–1.18 (avg. 1.05); rostrum length: up to 0.66 on both ♀ and ♂.

Figure 24. 

Rhinusa linariae (Panzer, 1796) pupa habitus A ventral view B lateral view C dorsal view.

Figure 25. 

Rhinusa linariae (Panzer, 1796) pupa habitus A ventral view B dorsal view C lateral view (schemes). Abbreviations: a–pr–abdominal protuberances, h–pr–head protuberances, p–pr–pronotal protuberances, ur–urogomphi, setae: as–apical, d–dorsal, fes–femoral, l, ls–lateral, os–orbital, pas–postantennal, pls–posterolateral, rs–rostral, v–ventral.

Body. Integument white, moderately stout slightly curved. Head elongated protuberances (h–pr) present on head above eyes, weakly sclerotised. Rostrum moderately elongated, curved, in male usually only slightly shorter than in female almost 3 × as long as wide, reaching mesocoxae. Pronotum trapezoidal 3 × as wide as long. Pronotal protuberances (p–pr) conical, flattened, indistinct. Meso- and metanotum similar in size. Abdominal segments I–III almost identical in size; segments IV–VII tapering gradually, segment VIII narrow; segment IX reduced. Abdominal segment VIII dorsally with very small, rounded, weakly sclerotised abdominal protuberance (a–pr). Urogomphi (ur) very short, ending with sclerotised, sharp apexes (Fig. 24A–C).

Chaetotaxy. Well developed, setae variable in length, transparent. Head with one short os and short pas. Rostrum with a single short rs (Fig. 25A). Pronotum with two as, two ls, and three elongated, equal-in-length pls. Dorsal parts of meso- and metathorax with a single medium-length seta, placed medially. Apex of femora with a single long fes (Fig. 25A–C). Abdominal segments I–VII with two, equal-in-length setae dorsally: first placed posteromedially, second posterolaterally. Abdominal segment VIII with a single elongated seta medially. Each lateral part of abdominal segments I–VII with a single short seta. Ventral parts of abdominal segments I–VIII with two short setae. Abdominal segment IX with two short setae ventrally (Fig. 25A–C).

This species is widely distributed in all of Europe, Turkey, Kazakhstan, and western Siberia (Alonso-Zarazaga et al. 2023). It was introduced in North America, where it was approved for release for biological control of invasive toadflaxes (Linaria spp.) in Canada in 1995 and 1996 (Sing et al. 2016). Afterwards, a population was established at sites in British Columbia and Colorado (Sing et al. 2016; DiGirolomo et al. 2019). In Europe, the adults of this species are distinguishable from all the other species of Rhinusa by the shape of the rostrum, which is strongly curved in lateral view, and the shape of the tibiae, with the uncus of the metatibiae of the same length in both sexes and with the outer margin distinctly curved outwards apically (Caldara and Toševski 2019).

Rhinusa linariae is a univoltine root galling weevil. Gall induction and larval development are mainly recorded on Linaria vulgaris and rarely on L. genistifolia in Southeastern Europe. Adults emerge in early spring, feed, and copulate on top of the young toadflax shoots. During oviposition, females glue eggs onto toadflax roots or, rarely, below root crowns with oviposition fluid. Eggs are laid singly or in small groups. Shortly after, oviposition triggers cell proliferation, which entwists the egg, forming a round gall. Larvae feed on galled root tissue through three instars. Pupation occurs in galls, while new adults emerge in mid- to late summer or rarely stay inside galls during winter, overwintering in soil or in plant litter close to their host plant. Twenty-five years ago, R. linariae was introduced as a biological control agent for invasive toadflaxes in Canada and the USA, where it was recently confirmed as established only in British Columbia. However, the current populations are still too small to have a significant biological impact (Sing et al. 2016; DiGirolomo et al. 2019).

4 mature larvae; 3 ♂ and 5 ♀ pupae. Serbia, Zemun, ex Linaria vulgaris galls, 01.06.2018, leg., det. I. Toševski.

(Figs 26A, B, 27A–E, 28A–C). Measurements (in mm). Body length: 4.00–5.75 (avg. 4.25). The widest place in the body (meso- and metathorax) measures up to 1.50. Head width: 0.60–0.68 (avg. 0.65).

Figure 26. 

Rhinusa pilosa (Gyllenhal, 1838) mature larva A habitus B head, frontal view.

Figure 27. 

Rhinusa pilosa (Gyllenhal, 1838) mature larva, head and mouth parts A head B antenna C clypeus and labrum (left side), epipharynx (right side) D left mandible E maxillolabial complex (schemes). Abbreviations: at–antenna, lr–labral rods, sb–sensillum basiconicum, Se–sensorium, st–stemmata, setae: als–anterolateral, ams–anteromedial, cls–clypeal, des–dorsal epicranial, dms–dorsal malar, fs–frontal epicranial, les–lateral epicranial, ligs–ligular, lrs–labral, mbs–malar basiventral, mds–mandibular dorsal, mpxs–maxillary palp, pes–postepicranial, pfs–palpiferal, pms–postmental, prms–premental, stps–stipital, ves–ventral, vms–ventral malar.

Figure 28. 

Rhinusa pilosa (Gyllenhal, 1838) mature larva, habitus A lateral view of thoracic segments B lateral view of abdominal segment I C lateral view of abdominal segments VII–X (schemes). Abbreviations: Th. 1–3–number of thoracic segments, Abd. 1–10–number of abdominal seg, setae: as–alar, ds–dorsal, eps–epipleural, eus–eusternal, lsts–laterosternal, pda–pedal, pds–postdorsal, prns–pronotal, ss–spiracular, ps–pleural, sts–sternal.

General. Body elongate, slightly curved, rounded in cross section (Fig. 26A). Prothorax slightly smaller than mesothorax, pronotal shield not pigmented. Meso- and metathorax equal in size; each divided dorsally into two folds (prodorsal fold distinctly smaller than postdorsal fold); postdorsal fold of metathorax conical. Pedal folds of thoracic segments isolated, prominent. Abdominal segments I–VI of similar size, next segments tapering towards posterior body end. Abdominal segments I–VII each divided dorsally into two folds of almost identical size; postdorsal folds of segments I–VI higher than prodorsal folds. Segments VIII and IX dorsally undivided. Epipleural folds of segments I–VIII conical. Laterosternal and eusternal folds of segments I–VIII weakly isolated. Abdominal segment X divided into four folds of equal size. Anus situated ventrally, almost completely covered with the ninth abdominal segment.

All spiracles unicameral; thoracic spiracles (Fig. 26A) placed laterally close to mesothorax; abdominal spiracles (Fig. 26A) placed anteromedially on segments I–VIII.

Colouration. Light yellow to dark yellow head, medial parts of epicranium less sclerotised (Fig. 26B). All thoracic and abdominal segments whitish (Fig. 26A). Cuticle covered with asperities.

Vestiture. Setae on body thin, transparent, different in length (very short or medium).

Head capsule (Figs 26B, 27A). Head wide, endocarinal line present, reaching to 2/3 length of frons. Frontal sutures on head indistinct, very wide. Single pair of stemmata in the form of small black spots (st) close to the end of the frontal suture. Des₁ short, located in middle part of epicranium; medium des₂; long des₃ located anteriorly on epicranium close to the border with the frontal suture; des₄ minute; and des₅ long, located anterolaterally above stemma (Fig. 27A). Fs₁ and fs₂ absent; fs₃ minute; fs₄ medium, located anteriorly; and long fs₅ located anterolaterally, close to antenna (Fig. 27A). Les₁ and les₂ medium; single short ves. Epicranial area with a single pes.

Antennae placed distally of the frontal suture, on the inside; membranous and distinctly convex basal article bearing one conical relatively short sensorium, plus three sensilla basiconica (Fig. 27B).

Clypeus and labrum (Fig. 27C) completely fused, trapezoidal, 3 × as wide as long, with two short cls, localised posteriorly three medium piliform lrs, located anteromedially. Epipharynx (Fig. 27C) with two finger-like elongated als; and two piliform ams, variable in length; labral rods (lr) indistinct, close to oval-shape; anterior border almost straight.

Mouth parts. Mandibles (Fig. 27D) bifid, cutting edge with blunt additional teeth; two short piliform mds, close to lateral border. Maxillolabial complex: maxilla more sclerotised than labium (Fig. 27E) stipes with one stps, two pfs and one very short mbs and one sensillum, stps and both pfs_1–2 relatively short; mala with four finger-like dms variable in length; four piliform vms, medium to short in length. Maxillary palpi two-segmented; basal palpomere distinctly wider than distal one; length ratio of basal and distal palpomeres almost 1:2; basal palpomere with short mpxs and two sensilla, distal palpomere with a group of five apical sensilla in terminal receptive area. Prementum (Fig. 27E) oval-shaped, with one short prms; ligula with round margin and two minute ligs; premental sclerite vestigial, only lateral parts highly sclerotised, posterior extension absent. Labial palpi one-segmented; palpi very small, with a single pore, and a group of three or four apical sensilla (ampullacea) on terminal receptive area; surface of labium smooth. Postmentum (Fig. 27E) with three pms, short pms₁ located posteromedially, medium pms₂ located mediolaterally, and short pms₃ located anterolaterally; membranous area smooth.

Thorax. Prothorax (Fig. 28A) with seven elongated to medium prns; two medium ps; and single short eus. Mesothorax (Fig. 28A) without prs; with two medium pds; one medium as; three ss (two medium and one short); one medium eps; one medium ps; and single minute eus. Chaetotaxy of metathorax (Fig. 28A) almost identical to that of mesothorax. Each pedal area of thoracic segments with five pda of various length.

Abdomen. Segments I–VIII (Fig. 28B, C) without prs; with two medium pds; one minute and one medium ss; one medium eps; one medium ps; one short lsts; and two minute eus. Abdominal segment IX (Fig. 28C) with two minute ds; one minute ps; and two minute sts.

(Figs 29A–C, 30A–C). Measurements (in mm). Body length: 2.86–3.75 (avg. 3.25); body width: 1.90–2.25 (avg. 2.00); thorax width: 1.10–1.35 (avg. 1.25); rostrum length: up to 0.40 ♂, ♀.

Figure 29. 

Rhinusa pilosa (Gyllenhal, 1838) pupa habitus A ventral view B lateral view C dorsal view.

Figure 30. 

Rhinusa pilosa (Gyllenhal, 1838) pupa habitus A ventral view B dorsal view C lateral view (schemes). Abbreviations: h–pr–head protuberances, ur–urogomphi, setae: as–apical, d–dorsal, fes–femoral, l, ls–lateral, os–orbital, pas–postantennal, pls–posterolateral, v–ventral.

Body. Integument white, with some parts dark sclerotised; moderately elongated, curved. Head protuberances (h–pr) elongated. Rostrum rather stout, on both sexes almost 2.3 × as long as wide, extended only to procoxae. Pronotum trapezoidal 3 × as wide as long. Pronotal protuberances (p–pr) absent. Meso- and metanotum similar in size. Abdominal segments I–VI almost identical in size; segment VII semicircular; segment VIII narrow; segment IX reduced. Abdominal protuberances (a–pr) absent. Urogomphi (ur) medium-sized, ending with sclerotised, sharp apexes (Fig. 29A–C).

Chaetotaxy. Well developed, setae minute to elongated. Minute and medium setae transparent, elongated setae basally brown, apically transparent. Head with one minute os (Fig. 30A). Rostrum with a single minute pas. Pronotum with three as, single ls, and two pls; all pronotal setae almost equally in length, prominent, basally brownish, apically transparent. Dorsal parts of meso- and metathorax with two identical in length setae, placed medially. Setae of mesothorax as long as those on pronotum. Apex of femora with a single long fes (Fig. 30A–C). Abdominal segments I–VI with three setae: first and second minute placed anteromedially, third medium placed below stigma. Abdominal segments VII with three elongated setae dorsally and segment VIII with two elongated setae dorsally. Each lateral part of abdominal segments I–VII with a single medium seta. Ventral parts of abdominal segments I–VIII with two minute setae. Abdominal segment IX with two minute setae ventrally (Fig. 30A–C).

This species is distributed in northern and central Europe and in the Balkans (Alonso-Zarazaga et al. 2023). It is distinguishable from other species of the R. pilosa group by the rostrum being markedly bent at the level of antennal insertion in both sexes. It is a unique species in the group in being distributed northwards in the western Palaearctic, associated only with L. vulgaris as a host plant. All three species of this group differ from the other species of Rhinusa by the very long, hair-like scales of the dorsal vestiture.

Rhinusa pilosa is a shoot-galling weevil associated with L. vulgaris for larval development. Adults become active in early spring, and their appearance after winter hibernation coincides with the intensive shoot growth of their host plant. Females oviposit in the upper part of the young, growing shoots of L. vulgaris. Females oviposit three to six eggs, but the number of ovipositions has been observed to exceed 17 per shoot. Oviposition provokes the induction of a globose or elyptical gall on the apical part of the stem. Larvae feed and complete development within the induced galls. Pupation is also completed within the gall. Eclosed adults intensively feed on gall tissue, after which they leave the gall and enter into summer aestivation within the soil litter or soil cracks. In late autumn, adults are briefly active, feeding on young L. vulgaris shoots before entering diapause, sheltering close to the host plant. The biology of R. pilosa is described in detail by Gassmann et al. (2014).

2 mature larvae, 26.04.2014; 1♂ and 3♀ pupae, 10.05.2014; 8 mature larvae; 2♂ and 2♀ pupae, 12.05.2014, ex Linaria dalmatica, Serbia, Staničenje, Pirot, leg., det. I. Toševski.

(Figs 31A, B, 32A–E, 33A–C). Measurements (in mm). Body length: 3.00–4.25 (avg. 3.60). The widest place in the body (meso- and metathorax) measures up to 1.25. Head width: 0.55–0.60 (avg. 0.56).

Figure 31. 

Rhinusa rara Toševski & Caldara, 2015 mature larva A habitus B head, frontal view.

Figure 32. 

Rhinusa rara Toševski & Caldara, 2015 mature larva, head and mouth parts A head B antenna C clypeus and labrum (left side), epipharynx (right side) D left mandible E maxillolabial complex (schemes). Abbreviations: at–antenna, lr–labral rods, st–sensillum styloconicum, Se–sensorium, st–stemmata, setae: als–anterolateral, ams–anteromedial, cls–clypeal, des–dorsal epicranial, dms–dorsal malar, fs–frontal epicranial, les–lateral epicranial, ligs–ligular, lrs–labral, mbs–malar basiventral, mds–mandibular dorsal, mpxs–maxillary palp, pes–postepicranial, pfs–palpiferal, pms–postmental, prms–premental, stps–stipital, vms–ventral malar.

Figure 33. 

Rhinusa rara Toševski, Caldara, 2015 mature larva, habitus A lateral view of thoracic segments B lateral view of abdominal segment I C lateral view of abdominal segments VII–X (schemes). Abbreviations: Th. 1–3–number of thoracic segments, Abd. 1–10–number of abdominal seg, setae: ds–dorsal, eps–epipleural, pda–pedal, pds–postdorsal, prns–pronotal, prs–prodorsal, ss–spiracular, ps–pleural, sts–sternal.

General. Body elongate, slender, distinctly curved, rounded in cross section (Fig. 31A). All thoracic segments almost equal in size. Meso- and metathorax each divided dorsally into two folds (prodorsal fold distinctly smaller than postdorsal fold). Pedal folds of thoracic segments isolated, conical, prominent. Abdominal segments I–VI of similar size, next segments tapering towards posterior body end. Abdominal segments I–VII each divided dorsally into two folds: prodorsal fold slightly smaller than postdorsal, which form conical, prominent protuberances apically. Segments VIII and IX dorsally undivided. Epipleural folds of segments I–VIII conical. Laterosternal and eusternal folds of segments I–VIII conical, weakly isolated. Abdominal segment X (almost completely hidden in previous segment) divided into four folds of equal size. Anus situated ventrally.

All spiracles unicameral; thoracic spiracles (Fig. 31A) placed laterally close to mesothorax; abdominal spiracles (Fig. 31A) placed medio-laterally on segments I–VIII.

Colouration. Light yellow to yellow head, medial parts of epicranium less sclerotised (Fig. 31B). All thoracic and abdominal segments white (Fig. 31A). Cuticle covered with asperities.

Vestiture. Setae on body thin, yellowish, different in length (very short or medium).

Head capsule (Figs 31B, 32A). Head wide, endocarinal line present, reaching to 2/3 length of frons. Frontal sutures on head very wide, indistinct. Single pair of stemmata in the form of small black spots (st) laterally to the end of the frontal suture. Des₁ short; des₂ short, located in lateral part of epicranium; long des₃ located anteriorly on epicranium on border of the frontal suture; des₄ absent; and des₅ long, located anterolaterally above stemma (Fig. 32A). Fs₁ and fs₂ absent; fs₃ minute, located medially; fs₄ long, located anteriorly; and long fs₅ located anterolaterally, close to antenna (Fig. 32A). Les₁ and les₂ medium. Epicranial area with a single pes.

Antennae placed distally of the frontal suture, on the inside; membranous and distinctly convex basal article bearing one conical elongate sensorium, plus five sensilla styloconica (Fig. 32B).

Clypeus and labrum (Fig. 32C) completely fused, trapezoidal, 2.7 × as wide as long, with two minute cls, localised posterolaterally; three piliform lrs, various long; lrs₁ and lrs₂ medium, located anteromedially, and lrs₃ short, located laterally; anterior border almost straight. Epipharynx (Fig. 32C) with two finger-like als, variable in length and two ams variable in length; labral rods (lr) indistinct, rounded; anterior border sinuate.

Mouth parts. Mandibles (Fig. 32D) bifid, cutting edge with additional protuberance; two medium piliform mds, both located close to lateral border. Maxillolabial complex: maxilla more sclerotised than labium (Fig. 32E) stipes with one stps, two pfs and one very short mbs, stps and both pfs_1–2 relatively short; mala with four piliform dms variable in length; two short piliform vms. Maxillary palpi two-segmented; basal palpomere distinctly wider and slightly longer than distal one; basal palpomere with short mpxs and single sensillum, distal palpomere with a group of four or five apical sensilla in terminal receptive area. Prementum (Fig. 32E) close to oval-shaped, with one short prms; ligula with slightly sinuate margin and three minute ligs; premental sclerite sclerotised U-shaped. Labial palpi one-segmented; each palp with a single pore, and a group of three or four apical sensilla (ampullacea) on terminal receptive area; surface of labium smooth. Postmentum (Fig. 32E) with only two pms, medium pms₁ located medially and short pms₂ located laterally, pms₃ absent; membranous area smooth.

Thorax. Only pronotal and single pedal setae elongated, rest of thoracic minute, feebly visible. Prothorax (Fig. 33A) with four prns and two ps. Mesothorax (Fig. 33A) with one prs, three pds; three ss; one eps and one ps. Chaetotaxy of metathorax (Fig. 33A) almost identical to that of mesothorax. Each pedal area of thoracic segments with three minute and one elongated pda.

Abdomen. All abdominal setae minute, feebly visible. Segments I–VIII (Fig. 33B, C) with one prs; three pds; one ss; one eps; one ps and one lsts. Abdominal segment IX (Fig. 33C) with a single ds, single ps, and single sts.

(Figs 34A–C, 35A–C). Measurements (in mm). Body length: 3.35–3.85 (avg. 3.75); body width: 1.60–2.10 (avg. 1.75); thorax width: 1.05–1.30 (avg. 1.20); rostrum length: up to 1.50 for both sexes.

Figure 34. 

Rhinusa rara Toševski & Caldara, 2015 pupa habitus A ventral view B lateral view C dorsal view.

Figure 35. 

Rhinusa rara Toševski & Caldara, 2015 pupa habitus A ventral view B dorsal view C lateral view (schemes). Abbreviations: h–pr–head protuberances, ur–urogomphi, setae: as–apical, d–dorsal, fes–femoral, l–lateral, pls–posterolateral, v–ventral.

Body. Integument white, moderately elongated, curved. Head protuberances (h–pr) above eyes present. Rostrum rather short, in male usually only slightly shorter than in female almost 2.5 × as long as wide, reaching mesocoxae. Pronotum trapezoidal 2 × as wide as long. Pronotal protuberances (p–pr) absent. Meso- and metanotum similar in size. Abdominal segments I–VI almost identical in size; segment VII semicircular; segment VIII narrow; segment IX reduced. Urogomphi (ur) short, ending with sclerotised, sharp apexes (Fig. 34A–C).

Chaetotaxy. Well developed, setae short to elongated, short setae transparent, elongated brown. Head and rostrum without seta (Fig. 35A). Pronotum with three as, and three pls almost equally in length. Dorsal parts of meso- and metathorax with two setae of similar length, placed medially. Apex of femora with a single long fes (Fig. 35A–C). Abdominal segments I–VI with four short setae dorsally, all placed close to posterior margin. Abdominal segment VII with three elongated setae dorsally. Abdominal segment VIII with two elongated setae dorsally. Each lateral part of abdominal segments I–VII with a single short seta. Ventral parts of abdominal segments I–VIII with two short setae. Abdominal segment IX with two short setae ventrally (Fig. 35A–C).

This species is very restricted in its distribution and scarce. It is known only from calcareous regions in Serbia (Sićevo Gorge between the towns of Niš and Pirot), Hungary (Balaton), southern Slovakia (Šturovo), southern Czechia (Znojmo), Austria (Wien) and southern Russia (Toševski et al. 2015). It differs from the other European species of the R. pilosa group in its evenly curved rostrum in lateral view in both sexes (vs. abruptly narrowed and bent along the dorsal margin), almost flat pronotum and elytra (vs. moderately convex), and integument of adults covered with recumbent hair-like scales (vs. suberect hair-like scales).

The biology of R. rara is similar to that of R. pilosa. The adults become active in the field very early, often in mid-February. The adults are hidden inside the rosette of the host plant, L. genistifolia or L. dalmatica. The females oviposit at the base of young, growing shoots. Induced galls are usually large, partly hidden below the soil surface. Usually, ~ 10 eggs are laid per shoot, but some shoots can be used for 20 or more ovipositions. The biology of R. rara is described in detail by Toševski et al. (2015).

20 mature larvae; 6 ♂ and 6 ♀ pupae. Serbia, Sredrievo, ex Kickxia elatine (L.) Dumort., 15.08.2017, leg., det. I. Toševski.

(Figs 36A, B, 37A–E, 38A–C). Measurements (in mm). Body length: 2.50–4.00 (avg. 3.40). The widest place in the body (meso- and metathorax) measures up to 1.50. Head width: 0.50–0.55 (avg. 0.55).

Figure 36. 

Rhinusa herbarum (H. Brisout de Barneville, 1862) mature larva A habitus B head, frontal view.

Figure 37. 

Rhinusa herbarum (H. Brisout de Barneville, 1862) mature larva, head and mouth parts A head B antenna C clypeus and labrum (left side), epipharynx (right side) D left mandible E maxillolabial complex (schemes). Abbreviations: at–antenna, lr–labral rods, sb–sensillum basiconicum, Se–sensorium, st–stemmata, setae: als–anterolateral, ams–anteromedial, cls–clypeal, des–dorsal epicranial, dms–dorsal malar, fs–frontal epicranial, les–lateral epicranial, ligs–ligular, lrs–labral, mbs–malar basiventral, mds–mandibular dorsal, mpxs–maxillary palp, pes–postepicranial, pfs–palpiferal, pms–postmental, prms–premental, stps–stipital, ves–ventral, vms–ventral malar.

Figure 38. 

Rhinusa herbarum (H. Brisout de Barneville, 1862) mature larva, habitus A lateral view of thoracic segments B lateral view of abdominal segment I C lateral view of abdominal segments VII–X (schemes). Abbreviations: Th. 1–3–number of thoracic segments, Abd. 1–10–number of abdominal seg, setae: as–alar, ds–dorsal, eps–epipleural, eus–eusternal, lsts–laterosternal, pda–pedal, pds–postdorsal, prns–pronotal, prs–prodorsal, ss–spiracular, ps–pleural, sts–sternal.

General. Body elongate, slender, strongly curved, rounded in cross section (Fig. 36A). All thoracic segments equal in size. Meso- and metathorax each divided dorsally into two folds (prodorsal fold vestigial, postdorsal fold prominent). Pedal folds of thoracic segments well isolated. Abdominal segments I–V of similar size, next segments tapering towards posterior body end. Abdominal segments I–VII each divided dorsally into two folds almost identical in size. Segments VIII and IX dorsally undivided. Epipleural folds of segments I–VIII conical well developed. Laterosternal and eusternal folds of segments I–VIII conical, well isolated. Abdominal segment X divided into four folds of equal size. Anus situated ventrally, almost completely hidden in the ninth segment.

Thoracic and abdominal spiracles unicameral; thoracic spiracles (Fig. 36A) placed laterally close to mesothorax; abdominal spiracles (Fig. 36A) placed medially on segments I–VIII.

Colouration. Almost white to light yellow head (Fig. 36B). All thoracic and abdominal segments whitish (Fig. 36A). Cuticle covered with asperities.

Vestiture. Setae on body thin, transparent, different in length (minute to medium).

Head capsule (Figs 36B, 37A). Head suboval, endocarinal line present, reaching to 2/3 length of frons. Frontal sutures on head indistinct, very wide. Single pair of stemmata in the form of small black spots (st) placed laterally, close to the end of the frontal suture. Des₁ short, located in middle part of epicranium; long des₂ located anteriorly; long des₃ placed almost on the border of the frontal suture; minute des₄, located laterally; and long des₅ placed anterolaterally above stemma (Fig. 37A). Fs₁ absent; fs₂ short, located posterolaterally; fs₃ absent; fs₄ long, located anteriorly; and long fs₅ located anterolaterally, close to antenna (Fig. 37A). Les₁ and les₂ medium; two short ves. Epicranial area with five pes.

Antennae placed distally of the frontal suture, on the inside; membranous and distinctly convex basal article bearing one conical elongate sensorium, plus three sensilla basiconica (Fig. 37B).

Clypeus (Fig. 37C) trapezoidal, ~ 2.5 × as wide as long with two short cls, localised posterolaterally, with one sensillum between them; anterior part distinctly less sclerotised than the basal part and slightly rounded towards the inside.

Mouth parts. Labrum (Fig. 37C) ~ 2.2 × as wide as long, with three piliform lrs, various long; lrs₁ and lrs₂ elongated, located medially on small protuberances, and lrs₃ medium, located anterolaterally; anterior border bi-sinuate. Epipharynx (Fig. 37C) with two elongated finger-like als, identical in length and three piliform ams variable in length; labral rods (lr) distinct, rounded. Mandibles (Fig. 37D) bifid, cutting edge straight; two medium piliform and short mds, both located close to lateral border. Maxillolabial complex: maxilla brownish sclerotised (Fig. 37E), stipes with one stps, two pfs and one mbs, stps and both pfs_1–2 elongated; mala with five finger-like dms variable in length; four medium piliform vms. Maxillary palpi two-segmented; basal palpomere distinctly wider than distal one, with short mpxs and two sensilla, distal palpomere with a group of two apical sensilla in terminal receptive area. Prementum (Fig. 37E) close to oval-shaped, with two prms variable in length; ligula with slightly sinuate margin and two short ligs; premental sclerite broad, sclerotised, cup-shaped, posterior extension medium, with thick apex. Labial palpi one-segmented; palpi with a single pore, and single, apical sensilla in terminal receptive area; surface of labium smooth. Postmentum (Fig. 37E) with three pms, short pms₁ located posteromedially, long pms₂ located mediolaterally, and short pms₃ located anterolaterally; membranous area partially covered with knobby asperities.

Thorax. Prothorax (Fig. 38A) with nine medium to short prns; two medium ps; and single short eus. Mesothorax (Fig. 38A) with a single minute prs; three medium pds; one medium as; three minute ss; one medium eps; one medium ps; and single minute eus. Chaetotaxy of metathorax (Fig. 38A) almost identical to that of mesothorax. Each pedal area of thoracic segments with four short to minute pda.

Abdomen. Segments I–VIII (Fig. 38B, C) without prs; with four pds of various length; one minute and one medium ss; single, medium eps; one medium ps; one minute lsts; and two minute eus. Abdominal segment IX (Fig. 38C) with one medium and one minute ds; one minute ps; and two minute sts.

(Figs 39A–C, 40A–C). Measurements (in mm). Body length: 2.25–3.10; body width: 1.50–1.80; thorax width: 0.70–1.05; rostrum length: up to 0.70 ♂ and 1.20 ♀.

Figure 39. 

Rhinusa herbarum (H. Brisout de Barneville, 1862) pupa habitus A ventral view B lateral view C dorsal view.

Figure 40. 

Rhinusa herbarum (H. Brisout de Barneville, 1862) pupa habitus A ventral view B dorsal view C lateral view (schemes). Abbreviations: a–pr–abdominal protuberances, h–pr–head protuberances, setae: as–apical, d–dorsal, ds–discal, l, ls–lateral, os–orbital, pls–posterolateral, rs–rostral, sos– supraorbital, v–ventral.

Body. Integument white moderately elongated. Head and pronotum without protuberances. Rostrum rather short, reaching to mesocoxae; in both sexes 2.2 × as long as wide. Clubs covered with knobby protuberances. Pronotum trapezoidal, 2 × as wide as long. Meso- and metanotum similar in size. Abdominal segments I–IV almost identical in size; segments VI and VI tapering gradually, VII semicircular; segment VIII narrow; segment IX reduced. Abdominal segments VII and VIII each with semicircular, weakly sclerotised abdominal protuberances (a–pr_{1, 2}). Urogomphi absent (Fig. 39A–C).

Chaetotaxy. Well-developed setae, elongated to short, transparent. Head with a single short sos, single short os. Rostrum with a single short rs (Fig. 40A). Pronotum with three as, single ls, single ds and three pls; all pronotal setae elongated, equal in length. Dorsal parts of meso- and metathorax with two medium setae, placed medially (Fig. 40A–C). Abdominal segments I–VIII dorsally with three short setae dorsally, placed close to posterior margin of the segments. Each lateral part of abdominal segments I–VIII with a single short seta. Ventral parts of abdominal segments I–VIII with two short setae. Abdominal segment IX with two short setae ventrally (Fig. 40A–C).

This species is distributed in Central and Southern Europe and in North Africa (Alonso-Zarazaga et al. 2023). The shape of the rostrum in adults is similar in lateral view to that of some species of the R. antirrhini group but not in dorsal view, where the basal half in cross section is normally rectangular and not trapezoidal, and the scrobes are only slightly visible (Caldara and Toševski 2019).

The host plants are Kickxia elatine and K. spuria (L.) Dumort. The females oviposit in the seed capsules of the host plant during the summer, following the phenology of plant flowering. Larvae complete their development and pupate inside seed capsules. The new adults emerge in late summer (Caldara and Toševski 2019).

8 mature larvae; 3 ♂ and 3 ♀ pupae. Serbia, Knjaževac, ex Linaria vulgaris inside R. linariae galls, 05.07.2017, leg., det. I. Toševski.

(Figs 41A, B, 42A–E, 43A–C). Measurements (in mm). Body length: 2.60–3.00 (avg. 2.75). The widest place in the body (meso- and metathorax) measures up to 0.90. Head width: 0.55–0.65 (avg. 0.60).

Figure 41. 

Rhinusa collina (Gyllenhal, 1813) mature larva A habitus B head, frontal view.

Figure 42. 

Rhinusa collina (Gyllenhal, 1813) mature larva, head and mouth parts A head B antenna C clypeus and labrum (left side), epipharynx (right side) D left mandible E maxillolabial complex (schemes). Abbreviations: at–antenna, lr–labral rods, sa–sensillum ampullaceum, sb–sensillum basiconicum, Se–sensorium, st–stemmata, setae: als–anterolateral, ams–anteromedial, cls–clypeal, des–dorsal epicranial, dms–dorsal malar, fs–frontal epicranial, les–lateral epicranial, ligs–ligular, lrs–labral, mbs–malar basiventral, mds–mandibular dorsal, mes–medial, mpxs–maxillary palp, pes–postepicranial, pfs–palpiferal, pms–postmental, prms–premental, stps–stipital, ves–ventral, vms–ventral malar.

Figure 43. 

Rhinusa collina (Gyllenhal, 1813) mature larva, habitus A lateral view of thoracic segments B lateral view of abdominal segment I C lateral view of abdominal segments VII–X (schemes). Abbreviations: Th. 1–3–number of thoracic segments, Abd. 1–10–number of abdominal seg, setae: as–alar, ds–dorsal, eps–epipleural, eus–eusternal, lsts–laterosternal, pda–pedal, pds–postdorsal, prns–pronotal, prs–prodorsal, ss–spiracular, ps–pleural, sts–sternal.

General. Body elongate, slender, distinctly curved, rounded in cross section (Fig. 41A). Prothorax prominent, pronotal shield not pigmented. Meso- and metathorax equal in size, smaller than prothorax; each divided dorsally into two folds (prodorsal fold distinctly smaller than postdorsal fold). Pedal folds of thoracic segments isolated, conical, prominent. Abdominal segments I–VI of similar size, next segments tapering towards posterior body end. Abdominal segments I–VII each divided dorsally into two various in size folds; postdorsal folds much higher than prodorsal folds. Segments VIII and IX dorsally undivided. Epipleural folds of segments I–VII conical. Laterosternal and eusternal folds of segments I–VIII conical, weakly isolated. Abdominal segment X divided into four folds of equal size. Anus situated ventrally, almost completely hidden in previous segment.

Thoracic and all abdominal spiracles unicameral; thoracic spiracles (Fig. 41A) placed ventrolaterally; abdominal spiracles (Fig. 41A) placed anteromedially on segments I–VIII.

Colouration. Dark yellow to light brown head, medial parts of epicranium less sclerotised (Fig. 41B). Frons and ventrolateral parts of the head covered with knobby asperities. All thoracic and abdominal segments whitish. Cuticle covered with fine asperities (Fig. 41A).

Vestiture. Setae on body thin, yellowish, different in length (minute to medium).

Head capsule (Figs 41B, 42A). Head suboval, endocarinal line present, reaching to 3/4 length of frons. Frontal sutures on head distinct, very wide. Two pairs of stemmata various in size in the form of small black spots (st); first medium size located close to end of frontal suture, second small placed mediolaterally. Des₁ long, located in middle part of epicranium; long des₂; long des₃ located anteriorly on epicranium close to the border with the frontal suture; des₄ very short; and des₅ elongated, located anterolaterally above stemma (Fig. 42A). Fs₁ and fs₂ absent; fs₃ minute, located medially; fs₄ long, located anteriorly; and long fs₅ located anterolaterally, close to antenna (Fig. 42A). Les₁ and les₂ medium; and two minute ves. Epicranial area with two pes.

Antennae placed distally of the frontal suture, on the inside; membranous and distinctly convex basal article bearing one conical elongate sensorium, plus three sensilla basiconica and single ampullacea (Fig. 42B).

Clypeus (Fig. 42C) trapezoidal, ~ 2.7 × as wide as long with two cls: cls₁ relatively long, cls₂ medium, both localised posterolaterally, with one sensillum between them; basal part distinctly more sclerotised than the apical part; anterior border slightly curved towards the inside.

Mouth parts. Labrum (Fig. 42C) ~ 2 × as wide as long, with three piliform lrs, various length; lrs₁ elongated, located posteromedially, lrs₂ elongated, located medially, and lrs₃ short, located anterolaterally; anterior border bi-sinuate. Epipharynx (Fig. 42C) with two elongated finger-like als, almost identical in length; two piliform ams equally in length; and single finger-like mes; labral rods (lr) distinct, close to kidney shape. Mandibles (Fig. 42D) bifid, cutting edge with a single, blunt protuberance; two medium piliform and single minute mds, all located close to lateral border. Maxillolabial complex: maxilla dark sclerotised (Fig. 42E), stipes with one stps, two pfs and one mbs and one sensillum, stps and both pfs_1–2 relatively long; mala with five finger-like dms variable in length (divided into two groups); four piliform vms, medium to short in length. Maxillary palpi two-segmented; basal palpomere distinctly wider than distal one; length ratio of basal and distal palpomeres almost 1:1; basal palpomere with short mpxs and two sensilla, distal palpomere with a group of three or four apical sensilla in terminal receptive area. Prementum (Fig. 42E) oval-shaped, with one long prms; ligula with slightly sinuate margin and two short ligs; premental sclerite broad, sclerotised, U-shaped. Labial palpi one-segmented; palpi with a single pore, and a group of two or three apical sensilla (ampullacea) on terminal receptive area; surface of labium smooth. Postmentum (Fig. 42E) with three pms, elongated pms₁ located posteromedially, elongated pms₂ located laterally, and medium pms₃ located anterolaterally; lateral parts of membranous area covered with distinct knobby asperities.

Thorax. Prothorax (Fig. 43A) with five medium prns: three placed apically, next two above stigma; two medium ps; and single short eus. Mesothorax (Fig. 43A) with one minute prs, two short and one medium pds (ordered: short, medium, short); one medium as; three ss (two medium and one minute); one medium eps; two medium ps; and single minute eus. Chaetotaxy of metathorax (Fig. 43A) almost identical to that of mesothorax. Each pedal area of thoracic segments with three medium and two minute pda.

Abdomen. Segments I–VIII (Fig. 43B, C) with one minute prs (segment VIII without); two minute and one medium pds; one minute and one medium ss; one medium eps; one short ps; one minute lsts; and two minute eus. Abdominal segment IX (Fig. 43C) with two minute ds; one minute ps; and two minute sts.

(Figs 44A–C, 45A–C). Measurements (in mm). Body length: 2.70–2.90 (avg. 2.75); body width: 1.75–1.80 (avg. 1.75); thorax width: 1.10–1.25 (avg. 1.15); rostrum length: up to 0.60 ♂ and 0.85 ♀.

Figure 44. 

Rhinusa collina (Gyllenhal, 1813) pupa habitus A ventral view B lateral view C dorsal view.

Figure 45. 

Rhinusa collina (Gyllenhal, 1813) pupa habitus A ventral view B dorsal view C lateral view (schemes). Abbreviations: a–pr–abdominal protuberances, p–pr–pronotal protuberances, ur–urogomphi, setae: as–apical, d–dorsal, ds–discal, fes–femoral, l, ls–lateral, os–orbital, pas–postantennal, pls–posterolateral, sos– supraorbital, v–ventral.

Body. Integument white, with some parts dark sclerotised; moderately stout, curved. Head with small head protuberances (h–pr) above eyes. Rostrum elongated, on both sexes almost 4 × as long as wide, distinctly protruding to mesocoxae. Pronotum trapezoidal 2.4 × as wide as long. Pronotal protuberances (p–pr) indistinct, flattened, sclerotised, separated at bases. Meso- and metanotum similar in size. Abdominal segments I–VI almost identical in size; segment VII semicircular; segment VIII narrow; segment IX reduced. Abdominal segment VIII dorsally with rounded, prominent, sclerotised abdominal protuberance (a–pr). Urogomphi (ur) medium, ending with sclerotised, sharp apexes (Fig. 44A–C).

Chaetotaxy. Well developed, setae medium to elongated, transparent. Head with one medium os and one elongated sos. Rostrum with a single pas (Fig. 45A). Pronotum with three as, one ds, two ls, and two pls variable in length. Dorsal parts of meso- and metathorax with three setae of various length, placed medially. Apex of femora with a single long fes (Fig. 45A–C). Abdominal segments I–VI with four setae dorsally, variable in length: first and third minute, second and fourth medium, placed close to posterior margin of the segment. Abdominal segments VII and VIII with three elongated setae dorsally. Each lateral part of abdominal segments I–VII with a single short seta. Ventral parts of abdominal segments I–VIII with three medium setae. Abdominal segment IX with two short setae ventrally (Fig. 45A–C).

This species is widely distributed in Europe (Alonso-Zarazaga et al. 2023). In adults, the shape of the rostrum, together with the moderately elongated body, are useful characters that easily distinguish this species from the others in the group.

Rhinusa collina is an inquiline weevil whose development is closely linked to root galls on L. vulgaris and L. genistifolia caused by R. linariae. The females oviposit eggs exclusively on well-developed galls that are not occupied by R. linariae larvae. For this reason, the competition of these inquiline weevils with gall inducers has never been observed (IT, pers. obs.).

9 mature larvae; 4 ♂ and 2 ♀ pupae. Serbia, Didići, ex Linaria vulgaris, 05.07.2017, leg., det. I. Toševski.

(Figs 46A, B, 47A–E, 48A–C). Measurements (in mm). Body length: 2.70–4.10 (avg. 3.10). The widest place in the body (meso- and metathorax) measures up to 1.30. Head width: 0.60–065 (avg. 0.62).

Figure 46. 

Rhinusa eversmanni (Rosenschoeld, 1838) mature larva A habitus B head, frontal view.

Figure 47. 

Rhinusa eversmanni (Rosenschoeld, 1838) mature larva, head and mouth parts A head B antenna C clypeus and labrum (left side), epipharynx (right side) D left mandible E maxillolabial complex (schemes). Abbreviations: at–antenna, lr–labral rods, sa–sensillum ampullaceum, sb–sensillum basiconicum, Se–sensorium, st–stemmata, setae: als–anterolateral, ams–anteromedial, cls–clypeal, des–dorsal epicranial, dms–dorsal malar, fs–frontal epicranial, les–lateral epicranial, ligs–ligular, lrs–labral, mbs–malar basiventral, mds–mandibular dorsal, mes–medial, mpxs–maxillary palp, pes–postepicranial, pfs–palpiferal, pms–postmental, prms–premental, stps–stipital, ves–ventral, vms–ventral malar.

Figure 48. 

Rhinusa eversmanni (Rosenschoeld, 1838) mature larva, habitus A lateral view of thoracic segments B lateral view of abdominal segment I C lateral view of abdominal segments VII–X (schemes). Abbreviations: Th. 1–3–number of thoracic segments, Abd. 1–10–number of abdominal seg, setae: as–alar, ds–dorsal, eps–epipleural, eus–eusternal, lsts–laterosternal, pda–pedal, pds–postdorsal, prns–pronotal, prs–prodorsal, ss–spiracular, ps–pleural, sts–sternal.

General. Body elongate, slender, strongly curved, rounded in cross section (Fig. 46A). All thoracic segments equal in size. Meso- and metathorax each divided dorsally into two folds (prodorsal fold vestigial, postdorsal fold prominent). Pedal folds of thoracic segments isolated, conical. Abdominal segments I–III of similar size, next segments tapering towards posterior body end. Abdominal segments I–VII each divided dorsally into two folds: postdorsal folds much higher than prodorsal folds. Segments VIII and IX dorsally undivided. Epipleural folds of segments I–VIII conical. Laterosternal and eusternal folds of segments I–VIII conical, well isolated. Abdominal segment X divided into four folds of equal size. Anus situated ventrally.

Thoracic and abdominal spiracles unicameral; thoracic spiracles (Fig. 46A) placed laterally close to mesothorax; abdominal spiracles (Fig. 46A) placed medially on segments I–VIII.

Colouration. Dark brown to brown head, medial parts of epicranium less sclerotised (Fig. 46B). Prodorsal sclerite brownish. All thoracic and abdominal segments whitish (Fig. 46A). Cuticle densely covered with cuticular asperities. All setae of thorax and abdomen placed on dark brown spots.

Vestiture. Setae on body thin, brown, different in length (minute to long).

Head capsule (Figs 46B, 47A). Head suboval, endocarinal line present, reaching to the 3/4 of the length of frons. Frontal sutures on head distinct, very wide. Frons covered with knobby, dark asperities. Single pair of stemmata in the form of small black spots (st) placed laterally, close to the end of the frontal suture. Des₁ long, located in middle part of epicranium; long des₂ located anteriorly; long des₃ placed almost on the border of the frontal suture; minute des₄, located laterally; and elongated des₅ placed anterolaterally above stemma (Fig. 47A). Fs₁ short, located posterolaterally; fs₂ and fs₃ absent; fs₄ long, located anteriorly; and long fs₅ located anterolaterally, close to antenna (Fig. 47A). Les₁ and les₂ medium; two short ves. Epicranial area with four pes.

Antennae placed distally of the frontal suture, on the inside; membranous and distinctly convex basal article bearing one conical, moderately elongate sensorium, plus a single sensillum ampullaceum and two sensilla basiconica (Fig. 47B).

Clypeus (Fig. 47C) trapezoidal, ~ 2.7 × as wide as long with two short cls, localised posterolaterally, with one sensillum between them; posterior part distinctly less sclerotised than the basal part; anterior border straight.

Mouth parts. Labrum (Fig. 47C) ~ 2.4 × as wide as long, with three piliform lrs, various long; lrs₁ and lrs₂ elongated, located medially, lrs₃ medium, located anterolaterally; anterior border bi-sinuate. Epipharynx (Fig. 47C) with three elongated finger-like als, almost identical in length; two piliform ams variable in length; single finger-like mes; labral rods (lr) distinct, kidney shaped. Mandibles (Fig. 47D) bifid, cutting edge with additional, blunt tooth; two medium piliform and short mds, both located close to lateral border. Maxillolabial complex: maxilla brownish sclerotised (Fig. 47E), stipes with one stps, two pfs and one short mbs and one sensillum, stps and both pfs_1–2 elongated; mala with five finger-like dms variable in length; four piliform vms, medium to short in length. Maxillary palpi two-segmented; basal palpomere wider and longer than distal one; basal palpomere with short mpxs and single sensillum, distal palpomere with a group of two or three apical sensilla in terminal receptive area. Prementum (Fig. 47E) close to oval-shaped, with one long prms; ligula with slightly sinuate margin and two short ligs; premental sclerite well sclerotised, U-shaped. Labial palpi one-segmented; palpi with a single pore, and a pair of apical sensilla (ampullacea) on terminal receptive area; surface of labium smooth. Postmentum (Fig. 47E) with three pms, medium pms₁ located posteromedially, long pms₂ located mediolaterally, and medium pms₃ located anterolaterally; membranous area partially covered with knobby asperities.

Thorax. Prothorax (Fig. 48A) with 12 elongated to short prns, ten of them placed on dorsal sclerite; two medium ps; and single short eus. Mesothorax (Fig. 48A) without prs; with two elongated and two short pds (ordered: short, long, short, long); one long as; two long and single minute ss; one long eps; two long ps; and single minute eus. Chaetotaxy of metathorax (Fig. 48A) almost identical to that of mesothorax. Each pedal area of thoracic segments with four relatively long and one minute pda.

Abdomen. Segments I–VIII (Fig. 48B, C) with one minute prs (segments VII and VIII without); four pds of various length; one minute and one long ss; three long eps; one long ps; one medium lsts; and two short eus. Abdominal segment IX (Fig. 48C) with two minute and one medium ds; one medium and one minute ps; and two minute sts.

(Figs 49A–C, 50A–C). Measurements (in mm). Body length: 2.36–2.76; body width: 1.73–2.00; thorax width: 1.03–1.20; rostrum length: up to 0.86 ♂ and 1.23 ♀.

Figure 49. 

Rhinusa eversmanni (Rosenschoeld, 1838) pupa habitus A ventral view B lateral view C dorsal view.

Figure 50. 

Rhinusa eversmanni (Rosenschoeld, 1838) pupa habitus A ventral view B lateral view C dorsal view (schemes). Abbreviations: a–pr–abdominal protuberances, p–pr–pronotal protuberances, ur–urogomphi, setae: as–apical, d–dorsal, ds–discal, fes–femoral, l, ls–lateral, os–orbital, pas–postantennal, pls–posterolateral, rs–rostral, sos– supraorbital, v–ventral.

Body. Integument white, stout. Head elongated protuberances present on head above eyes (h–pr). Rostrum elongated, reaching over mesocoxae (almost 4.2 × as wide as long on both male and female). Pronotum trapezoidal 2.5 × as wide as long. Pronotal setae placed on dark brown spots. Pronotal protuberances (p–pr) conical, flattened, sclerotised, separated at bases. Meso- and metanotum similar in size. Abdominal segments I–IV almost identical in size; segments V and VI tapering gradually, VII semicircular; segment VIII narrow; segment IX reduced. Urogomphi (ur) short, ending with sclerotised, sharp apexes (Fig. 49A–C).

Chaetotaxy. Well developed, setae elongated to short, transparent. Head with one medium sos and one medium os. Rostrum with a single rs (Fig. 50A). Pronotum with three as, three ls, and three pls all elongated, equal in length. Dorsal parts of meso- and metathorax with three setae of various length, placed medially. Apex of femora with a single long fes (Fig. 50A–C). Abdominal segments I–VII dorsally with four setae dorsally, variable in length: first and third minute, second, short, and fourth medium; setae first to third placed close to posterior margin of the segment, fourth placed below stigma (on segment VII all setae medium). Abdominal segments VII and VIII with four elongated setae dorsally. Each lateral part of abdominal segments I–VIII with one short seta. Ventral parts of abdominal segments I–VIII with three short setae. Abdominal segment IX with four short setae ventrally (Fig. 50A–C).

This is an uncommon species with a wide and fragmentary distribution: France, Italy, Germany, Czech Republic, Ukraine, Russia, Kazakhstan, Uzbekistan, and Tajikistan (Alonso-Zarazaga et al. 2023). At the adult stage, it is easily distinguishable from the other species of the group by the shape and length of the rostrum, especially in the female, which has a longer antennal club than all the other species of the genus.

The stem galls caused by R. pilosa on L. vulgaris and by R. rara on L. genistifolia or L. dalmatica are niches for the development of R. eversmanni, which is another inquiline weevil. The females oviposit their eggs on fully developed galls, and hatched larvae bore holes towards the central portion of the gall, where larvae of the gall inducer are positioned. Larvae of R. eversmanni are very aggressive, killing all resident larvae inside galls, while competition between them inside galls is pronounced and cannibalism is commonly observed. Over 20 adults of R. eversmanni can develop in the larger gall induced by R. pilosa or R. rara (Toševski et al. 2015).

5 mature larvae. Italia, Sicilia, San Cono, ex Linaria multicaulis (L.) Mill., 06.05.2017, leg. C. Baviera, det. R. Caldara.

(Figs 51A, B, 52A–E, 53A–C). Measurements (in mm). Body length: 2.25–3.00 (avg. 2.50). The widest place in the body (meso- and metathorax) measures up to 1.50. Head width: 0.60–070 (avg. 0.65).

Figure 51. 

Rhinusa incana (Kirsch, 1881) mature larva A habitus B head, frontal view.

Figure 52. 

Rhinusa incana (Kirsch, 1881) mature larva, head and mouth parts A head B antenna C clypeus and labrum (left side), epipharynx (right side) D left mandible E maxillolabial complex (schemes). Abbreviations: at–antenna, lr–labral rods, sb–sensillum basiconicum, Se–sensorium, st–stemmata, setae: als–anterolateral, ams–anteromedial, cls–clypeal, des–dorsal epicranial, dms–dorsal malar, fs–frontal epicranial, les–lateral epicranial, ligs–ligular, lrs–labral, mbs–malar basiventral, mds–mandibular dorsal, mes–medial, mpxs–maxillary palp, pes–postepicranial, pfs–palpiferal, pms–postmental, prms–premental, stps–stipital, ves–ventral, vms–ventral malar.

Figure 53. 

Rhinusa incana (Kirsch, 1881) mature larva, habitus A lateral view of thoracic segments B lateral view of abdominal segment I C lateral view of abdominal segments VII–X (schemes). Abbreviations: Th. 1–3–number of thoracic segments, Abd. 1–10–number of abdominal seg, setae: as–alar, ds–dorsal, eps–epipleural, eus–eusternal, lsts–laterosternal, pda–pedal, pds–postdorsal, prns–pronotal, prs–prodorsal, ss–spiracular, ps–pleural, sts–sternal.

General. Body elongate, slender, slightly curved, rounded in cross section (Fig. 51A). All thoracic segments equal in size. Meso- and metathorax each divided dorsally into two folds (prodorsal fold smaller than postdorsal fold). Pedal folds of thoracic segments isolated, conical. Abdominal segments I–V of similar size, next segments tapering towards posterior body end. Abdominal segments I–VII each divided dorsally into two folds: postdorsal folds much higher than prodorsal folds. Segments VIII and IX dorsally undivided. Epipleural folds of segments I–VIII conical. Laterosternal and eusternal folds of segments I–VIII conical, well isolated. Abdominal segment X divided into four folds of equal size. Anus situated ventrally, hidden in ninth segment.

Thoracic and abdominal spiracles unicameral; thoracic spiracles (Fig. 51A) placed laterally close to mesothorax; abdominal spiracles (Fig. 51A) placed medially on segments I–VIII.

Colouration. Yellow to brown head, medial parts of epicranium less sclerotised (Fig. 51B). All thoracic and abdominal segments whitish, covered with fine asperities (Fig. 51A).

Vestiture. Setae on body thin, transparent, different in length (minute to long).

Head capsule (Figs 51B, 52A). Head slightly narrowed bilaterally, endocarinal line present, reaching to 3/4 length of frons. Frontal sutures on head partially indistinct, very wide. Frons covered with knobby, dark asperities. Two pairs of stemmata in the form of small black spots (st) placed laterally. Des₁ very short, located in middle part of epicranium; medium des₂ located anteriorly; long des₃ placed almost on the border of the frontal suture; minute des₄, located laterally; and elongated des₅ placed close to stemma (Fig. 52A). Fs₁ minute, located posterolaterally; fs₂ and fs₃ minute; fs₄ medium, located anteriorly; and long fs₅ located anterolaterally, close to antenna (Fig. 52A). Les₁ and les₂ medium; two short ves. Epicranial area with three pes.

Antennae placed distally of the frontal suture, on the inside; membranous and distinctly convex basal article bearing one conical elongate sensorium, plus two sensilla basiconica (Fig. 52B).

Clypeus (Fig. 52C) trapezoidal, ~ 2.7 × as wide as long with two medium cls, localised posterolaterally, with one sensillum between them; anterior border straight.

Mouth parts. Labrum (Fig. 52C) ~ 2.4 × as wide as long, with three piliform lrs, various long; lrs₁ elongated, placed posteromedially, lrs₂ elongated, located anteromedially, lrs₃ medium, located anterolaterally; anterior border bi-sinuate. Epipharynx (Fig. 52C) with two elongated finger-like als, almost identical in length, two piliform ams variable in length and two finger-like mes variable in length; labral rods (lr) distinct, elongated. Mandibles (Fig. 52D) bifid, with two medium piliform mds, both located close to lateral border. Maxillolabial complex: maxilla brownish sclerotised (Fig. 52E) stipes with one stps, two pfs and one relatively long mbs and one sensillum, stps and both pfs_1–2 elongated; mala with five finger-like dms variable in length, placed in two groups (three + two); four piliform, vms, medium to short in length. Maxillary palpi two-segmented; basal palpomere slightly wider than distal one; basal palpomere with short mpxs and single sensillum, terminal receptive area of distal palpomere with a group of five or six apical sensilla; basal and distal palpomeres almost of the same length. Prementum (Fig. 52E) close to cup-shaped, with one long prms; ligula with distinctly sinuate margin and two ligs variable in length; premental sclerite well sclerotised, U-shaped. Labial palpi one-segmented; palpi with single pore; terminal receptive area with four or five apical sensilla (ampullacea); surface of labium smooth. Postmentum (Fig. 52E) with three pms, elongated pms₁ located posteromedially, long pms₂ located mediolaterally, and medium pms₃ located anterolaterally; membranous area smooth.

Thorax. Prothorax (Fig. 53A) with eight prns (four relatively long and four short); two elongated ps; and single short eus. Mesothorax (Fig. 53A) with minute prs, single short and two medium pds; one minute as; three minute ss; two long eps; single long ps; and single minute eus. Chaetotaxy of metathorax (Fig. 53A) almost identical to that of mesothorax. Each pedal area of thoracic segments with six relatively long pda.

Abdomen. Segments I–VIII (Fig. 53B, C) with one minute prs (segment VIII without); four medium pds; one minute and one medium ss; three medium eps; one medium ps; one medium lsts; and two minute eus. Abdominal segment IX (Fig. 53C) with two short and one minute ds; one medium and one minute ps; and two minute sts.

This species is distributed in the Iberian Peninsula, in southern Italy and Sicily, and in the western part of North Africa (Alonso-Zarazaga et al. 2023). It is very closely related to R. neta, from which it can be separated at adult stage by a few but constant characters (shape of the female rostrum, antennae inserted slightly more towards the base of the rostrum in both sexes, and scales of the dorsal vestiture slightly thinner).

This species was collected in Sicily inside the seed capsules of Linaria multicaulis subsp. aetnensis Giardina and Zizza, L. multicaulis subsp. humilis (Guss.) De Leon. (Baviera and Caldara 2020) and L. striata (Lam.) DC. (Goggi 2004). In Algeria, its development occurs inside the seed capsules of L. baborensis Batt. and L. heterophylla Desf. (de Peyerimhoff 1911).

21 mature larvae; 7 ♂ and 12 ♀ pupae. Serbia, Zemun, ex Linaria vulgaris, 15.08.2017, leg., det. I. Toševski.

(Figs 54A, B, 55A–E, 56A–C). Measurements (in mm). Body length: 4.60–7.00 (avg. 5.20). The widest place in the body (meso- and metathorax) measures up to 1.50. Head width: 0.62–0.75 (avg. 0.70).

Figure 54. 

Rhinusa neta (Germar, 1821) mature larva A habitus B head, frontal view.

Figure 55. 

Rhinusa neta (Germar, 1821) mature larva, head and mouth parts A head B antenna C clypeus and labrum (left side), epipharynx (right side) D left mandible E maxillolabial complex (schemes). Abbreviations: at–antenna, lr–labral rods, sa–sensillum ampullaceum, sb–sensillum basiconicum, Se–sensorium, st–stemmata, setae: als–anterolateral, ams–anteromedial, cls–clypeal, des–dorsal epicranial, dms–dorsal malar, fs–frontal epicranial, les–lateral epicranial, ligs–ligular, lrs–labral, mes–medial, mbs–malar basiventral, mds–mandibular dorsal, mpxs–maxillary palp, pes–postepicranial, pfs–palpiferal, pms–postmental, prms–premental, stps–stipital, ves–ventral, vms–ventral malar.

Figure 56. 

Rhinusa neta (Germar, 1821) mature larva, habitus A lateral view of thoracic segments B lateral view of abdominal segment I C lateral view of abdominal segments VII–X (schemes). Abbreviations: Th. 1–3–number of thoracic segments, Abd. 1–10–number of abdominal seg, setae: as–alar, ds–dorsal, eps–epipleural, eus–eusternal, lsts–laterosternal, pda–pedal, pds–postdorsal, prns–pronotal, prs–prodorsal, ss–spiracular, ps–pleural, sts–sternal.

General. Body elongate, moderately slender, curved, rounded in cross section (Fig. 54A). All thoracic segments equal in size. Meso- and metathorax each divided dorsally into two folds (prodorsal fold distinctly smaller than postdorsal fold). Pedal folds of thoracic segments isolated, conical, and prominent. Abdominal segments I–III of similar size, next segments tapering towards posterior body end. Abdominal segments I–VII each divided dorsally into two almost equal in size folds; postdorsal folds only slightly higher than prodorsal folds. Segments VIII and IX dorsally undivided. Epipleural folds of segments I–VIII conical. Laterosternal and eusternal folds of segments I–VIII conical, weakly isolated. Abdominal segment X divided into four folds of equal size, lateral folds each with a single minute seta. Anus situated ventrally, almost completely covered by ninth segment.

Thoracic and abdominal spiracles unicameral; thoracic spiracles (Fig. 54A) placed laterally close to mesothorax; abdominal spiracles (Fig. 54A) placed medially on segments I–VIII.

Colouration. Dark yellow to brown head, medial parts of epicranium less sclerotised (Fig. 54B). All thoracic and abdominal segments whitish, premental shield only slightly darker than the rest of prodorsum (Fig. 54A). Cuticle covered with asperities.

Vestiture. Setae on body thin, yellowish, different in length (very short or medium).

Head capsule (Figs 54B, 55A). Head suboval, endocarinal line present, reaching more than the 2/3 of the length of frons. Frontal sutures on head partially indistinct, wide. Frons covered with knobby, dark asperities. Single pair of stemmata in the form of small black spots (st) placed laterally, close to the end of the frontal suture. Des₁ short, located in middle part of epicranium; long des₂; long des₃ located anteriorly, almost on the border of the frontal suture; minute des₄ located laterally; and long des₅ placed anterolaterally above stemma (Fig. 55A). Fs₁ short, located posterolaterally; fs₂ and fs₃ absent; fs₄ medium, located anteriorly; and long fs₅ located anterolaterally, close to antenna (Fig. 55A). Les₁ and les₂ medium; two short ves. Epicranial area with three pes.

Antennae placed distally of the frontal suture, on the inside; membranous and distinctly convex basal article bearing one conical elongate sensorium, plus a single sensillum basiconicum and single sensillum ampullaceum (Fig. 55B).

Clypeus (Fig. 55C) trapezoidal, ~ 3.5 × as wide as long with two medium cls, localised posterolaterally, with one sensillum between them; basolateral parts distinctly more sclerotised than the middle part; anterior border slightly curved towards the inside.

Mouth parts. Labrum (Fig. 55C) ~ 2.5 × as wide as long, with three piliform lrs, variable in length; lrs₁ and lrs₂ elongated, located medially, lrs₃ short, located anterolaterally; anterior border bi-sinuate. Epipharynx (Fig. 55C) with three relatively elongated finger-like als, identical in length, three piliform ams variable in length and single short finger-like mes; labral rods (lr) elongated, close to kidney shaped. Mandibles (Fig. 55D) bifid, cutting edge smooth; two medium piliform and short mds, both located close to lateral border. Maxillolabial complex: maxilla brownish sclerotised (Fig. 55E), stipes with one stps, two pfs and one very short mbs and one sensillum, stps and both pfs_1–2 relatively long; mala with six finger-like dms variable in length; four piliform vms, medium to short in length. Maxillary palpi two-segmented; basal palpomere distinctly wider and slightly longer than distal one; basal palpomere with short mpxs and two sensilla, distal palpomere with a group of four apical sensilla in terminal receptive area. Prementum (Fig. 55E) close to oval-shaped, with one long prms; ligula with slightly sinuate margin and two medium ligs; premental sclerite weakly sclerotised, only lateral parts well visible. Labial palpi one-segmented; each palp with a single pore, and a group of three apical sensilla basiconica on terminal receptive area; surface of labium smooth. Postmentum (Fig. 55E) with three pms, medium pms₁ located anteromedially, long pms₂ located laterally, and medium pms₃ located anterolaterally; membranous area covered with knobby asperities.

Thorax. Prothorax (Fig. 56A) with eight medium to short prns; two medium ps; and single short eus. Mesothorax (Fig. 56A) with one minute prs, two medium and one minute pds (ordered: minute, medium, medium); one medium as; two medium and single minute ss; one medium eps; two medium ps; and single minute eus. Chaetotaxy of metathorax (Fig. 56A) almost identical to that of mesothorax. Each pedal area of thoracic segments with four relatively long and one minute pda.

Abdomen. Segments I–VIII (Fig. 56B, C) with one minute prs (segment VIII without); four pds of various length; one minute and one medium ss; three medium eps; one medium ps; one medium lsts; and two short eus. Abdominal segment IX (Fig. 56C) with one minute and one medium ds; one medium and one minute ps; and two minute sts.

(Figs 57A–C, 58A–C). Measurements (in mm). Body length: 2.70–4.20 (avg. 3.25); body width: 1.53–2.26 (avg. 2.10); thorax width: 1.00–1.53 (avg. 1.40); rostrum length: up to 0.73 ♂ and 0.83 ♀.

Figure 57. 

Rhinusa neta (Germar, 1821) pupa habitus A ventral view B lateral view C dorsal view.

Figure 58. 

Rhinusa neta (Germar, 1821) pupa habitus A ventral view B dorsal view C lateral view (schemes). Abbreviations: a–pr–abdominal protuberances, h–pr–head protuberances, p–pr–pronotal protuberances, ur–urogomphi, setae: as–apical, d–dorsal, ds–discal, fes–femoral, l, ls–lateral, os–orbital, pls–posterolateral, rs–rostral, sos– supraorbital, v–ventral.

Body. Integument white, with some parts dark sclerotised; moderately stout, curved. All setae placed on dark brown spots. Head elongated protuberances present (h–pr) on head above eyes. Rostrum elongated, on both sexes almost 4 × as long as wide, reaching over mesocoxae. Pronotum trapezoidal 2.2 × as wide as long. Pronotal protuberances (p–pr) conical, flattened, sclerotised, separated at bases. Meso- and metanotum similar in size. Abdominal segments I–IV almost identical in size; segments V and VI tapering gradually, VII semicircular; segment VIII narrow; segment IX reduced. Abdominal segment VIII dorsally with flattened, weakly sclerotised abdominal protuberance (a–pr). Urogomphi (ur) short, ending with sclerotised, sharp apexes (Fig. 57A–C).

Chaetotaxy. Well developed, setae medium to elongated, transparent. Head with one medium sos and one medium os. Rostrum with two rs (Fig. 58A). Pronotum with three as, single ls, and three pls all equal in length. Dorsal parts of meso- and metathorax with three setae of various length, placed medially. Apex of femora with a single long fes (Fig. 58A–C). Abdominal segments I–VII dorsally with five setae, variable in length: first and third minute, second, fourth, and fifth medium; setae first to fourth placed close to posterior margin of the segment, fifth placed below stigma (on segments VI and VII all setae medium in size). Abdominal segment VIII dorsally with four elongated setae dorsally. Each lateral part of abdominal segments I–VIII with two short setae. Ventral parts of abdominal segments I–VIII with three medium setae. Abdominal segment IX with three short setae ventrally (Fig. 58A–C).

This species is very common and has a wide distribution (western, central, and southern Europe, Caucasus, Iran, central Asia; Alonso-Zarazaga et al. 2023). It was accidentally introduced in North America (Buchanan 1937) but subsequently used as a biological control agent against the dalmatian toadflax (Linaria dalmatica) and yellow toadflax (Linaria vulgaris) (Sing et al. 2016). There are no noteworthy morphological differences between various populations living on different species of Linaria. The shape of the rostrum is the most useful character, which allows easy separation at adult stage of R. neta from the other species of the genus with short elytra, except for the western Mediterranean R. incana, from which it can be distinguished only by the shape of the female rostrum, the antennal insertion being located slightly more towards the apex of the rostrum in both sexes, and the scales of the dorsal vestiture being slightly stouter.

The descriptions of the larva and pupa of R. neta given by Ścibior and Łętowski (2018) are generally similar to ours, with some differences probably due to the nomenclature used by these authors. In our opinion, some setae were incorrectly identified in the larva, e.g., as₁ instead of ls₁. There are also some discrepancies in the interpretation of pupal characters, such as a lack of rs₂ or sos instead of os and four abdominal dorsal setae instead of five.

This is an oligophagous species whose larvae develop on different toadflaxes (Linaria spp.). The females oviposit eggs from mid-June to the end of September in an already developed seed capsule. The larvae are typical seed feeders. Larval development was recorded on many Linaria species: L. vulgaris, L. genistifolia, L. dalmatica, L. grandiflora Desf., L. angustissima, L. arvensis (L.) Desf., L. corifolia Desf., L. peloponnesiaca Boiss. and Heldr., L. repens (L.) Mill., L. rubioides Vis. & Pancic, L. spartea (L.) Chaz., L. supina (L.) Chaz., and L. vulgaris. Oviposition of eggs and larval feeding do not cause swelling of seeds, but larvae may consume a large proportion of seeds within a capsule, decreasing the seed output but not killing the host plant (Sing et al. 2016).

21 mature and 7 premature larvae; 7 ♂ and 11 ♀ pupae. France, Alpes-Maritimes, La Turbie, ex Antirrhinum majus L., 01.06.2014, leg., det. R. Caldara.

(Figs 59A, B, 60A–E, 61A–C). Measurements (in mm). Body length: 6.50–8.25 (avg. 7.50). The widest place in the body (meso- and metathorax) measures up to 2.50. Head width: 0.90–1.05 (avg. 1.00).

Figure 59. 

Rhinusa vestita (Germar, 1821) mature larva A habitus B head, frontal view.

Figure 60. 

Rhinusa vestita (Germar, 1821) mature larva, head and mouth parts A head B antenna C clypeus and labrum (left side), epipharynx (right side) D left mandible E maxillolabial complex (schemes). Abbreviations: at–antenna, lr–labral rods, sb–sensillum basiconicum, Se–sensorium, st–stemmata, setae: als–anterolateral, ams–anteromedial, cls–clypeal, des–dorsal epicranial, dms–dorsal malar, fs–frontal epicranial, les–lateral epicranial, ligs–ligular, lrs–labral, mbs–malar basiventral, mds–mandibular dorsal, mpxs–maxillary palp, pes–postepicranial, pfs–palpiferal, pms–postmental, prms–premental, stps–stipital, ves–ventral, vms–ventral malar.

Figure 61. 

Rhinusa vestita (Germar, 1821) mature larva, habitus A lateral view of thoracic segments B lateral view of abdominal segment I C lateral view of abdominal segments VII–X (schemes). Abbreviations: Th. 1–3–number of thoracic segments, Abd. 1–10–number of abdominal seg, setae: as–alar, ds–dorsal, eps–epipleural, eus–eusternal, lsts–laterosternal, pda–pedal, pds–postdorsal, prns–pronotal, prs–prodorsal, ss–spiracular, ps–pleural, sts–sternal.

General. Body elongate, moderately slender, slightly curved, rounded in cross section (Fig. 59A). Prothorax relatively small, pronotal shield not pigmented; meso- and metathorax equal in size, distinctly wider than prothorax. Meso- and metathorax each divided dorsally into two folds (prodorsal fold vestigial, postdorsal fold prominent). Pedal folds of thoracic segments isolated, conical. Abdominal segments I–III of similar size, as large as metathorax; segment IV the widest; next segments tapering towards posterior body end. Abdominal segments I–VII each divided dorsally into two folds various in size; postdorsal folds larger than prodorsal folds. Segments VIII and IX dorsally undivided. Epipleural folds of segments I–VII conical. Laterosternal and eusternal folds of segments I–VIII conical, well isolated. Abdominal segment X divided into four folds of equal size. Anus situated ventrally, almost completely hidden in previous segment.

All spiracles unicameral, thoracic spiracles (Fig. 59A) placed ventrolaterally; abdominal spiracles (Fig. 59A) placed anteromedially on segments I–VIII.

Colouration. Dark yellow to light brown head, medial parts of epicranium less sclerotised (Fig. 59B). All thoracic and abdominal segments white (Fig. 59A). Cuticle densely covered with cuticular asperities.

Vestiture. Setae on body well developed, yellowish, different in length (minute to medium).

Head capsule (Figs 59B, 60A). Head wide, endocarinal line present, reaching to the 3/4 of the length of frons. Frontal sutures on head distinct, very wide. Single pair of stemmata in the form of small black spots (st) close to the end of the frontal suture. Des₁ short, located in middle part of epicranium; long des₂; long des₃ located anteriorly on epicranium, close to border with frontal suture; des₄ short; des₅ elongated, located anterolaterally above stemma (Fig. 60A). Fs₁, fs₂ and fs₃ minute, located along frontal suture; fs₄ long, located anteriorly; and long fs₅ located anterolaterally, close to antenna (Fig. 60A). Les₁ and les₂ medium; two minute ves. Epicranial area with two pes.

Antennae placed distally of the frontal suture, on the inside; membranous and distinctly convex basal article bearing one conical, medium in length sensorium, plus four sensilla ampullacea (Fig. 60B).

Clypeus (Fig. 60C) trapezoidal, ~ 2.7 × as wide as long with two cls: cls₁ relatively long, cls₂ medium, both localised posterolaterally, with one sensillum between them; basal part distinctly more sclerotised than the apical part; anterior border slightly curved towards the inside.

Mouth parts. Labrum (Fig. 60C) ~ 2 × as wide as long, with three piliform lrs, various long; lrs₁ elongated, located posteromedially, lrs₂ elongated, located medially, and lrs₃ short, located anterolaterally; anterior border bisinuate. Epipharynx (Fig. 60C) with two elongated finger-like als, almost identical in length and three piliform ams equally in length; labral rods (lr) distinct, elongated, converging posteriorly. Mandibles (Fig. 60D) bifid, cutting edge with a single, blunt protuberance; two medium piliform and single minute mds, all located close to lateral border. Maxillolabial complex: maxilla dark sclerotised (Fig. 60E) stipes with one stps, two pfs and one short mbs and one sensillum, stps and both pfs_1–2 elongated; mala with six finger-like dms variable in length; four piliform vms, medium to short in length. Maxillary palpi two-segmented; basal palpomere distinctly wider than distal one; length ratio of basal and distal palpomeres almost 1:1; basal palpomere with short mpxs and two sensilla, distal palpomere with a group of three or four apical sensilla in terminal receptive area. Prementum (Fig. 60E) cup-shaped, with one medium prms; ligula with sinuate margin and two medium ligs; premental sclerite broad, highly sclerotised, Y-shaped, posterior extension with elongated apex. Labial palpi one-segmented; palpi with two pores, and a group of three or four apical sensilla (ampullacea) on terminal receptive area; surface of labium smooth. Postmentum (Fig. 60E) with three pms, medium pms₁ located posteromedially, elongated pms₂ located laterally, and medium pms₃ located anterolaterally; membranous area smooth.

Thorax. Prothorax (Fig. 61A) with five elongated and two medium prns: five placed apically, next two laterally; two elongated ps; and single short eus. Mesothorax (Fig. 61A) with one short and two medium pds (ordered: short, medium, medium); one medium as; three medium ss; one elongated eps; one elongated ps; and single minute eus. Chaetotaxy of metathorax (Fig. 61A) almost identical to that of mesothorax. Each pedal area of thoracic segments with two elongated, three medium and one minute pda.

Abdomen. Segments I–VIII (Fig. 61B, C) with one minute prs; one medium and two elongated pds; one minute and one elongated ss; two elongated eps; one medium ps; one medium lsts; and two minute eus. Abdominal segment IX (Fig. 61C) with two medium and single minute ds; one medium and one minute ps; and single minute sts.

(Figs 62A–C, 63A–C). Measurements (in mm). Body length: 4.75–6.50 (avg. 5.25); body width: 2.75–3.50 (avg. 3.15); thorax width: 1.60–2.00 (avg. 1.90); rostrum length: up to 1.25 ♂ and ♀.

Figure 62. 

Rhinusa vestita (Germar, 1821) pupa habitus A ventral view B lateral view C dorsal view.

Figure 63. 

Rhinusa vestita (Germar, 1821) pupa habitus A ventral view B dorsal view C lateral view (schemes). Abbreviations: p–pr–pronotal protuberances, ur–urogomphi, setae: as–apical, d–dorsal, ds–discal, fes–femoral, l, ls–lateral, os–orbital, pls–posterolateral, v–ventral.

Body. Integument white or light yellow, moderately elongated, slightly curved. Head with a pair of small head protuberances (h–pr) above eyes. Rostrum moderately stout, almost 2.5 × as long as wide, reaching mesocoxae, on both sexes. Pronotum trapezoidal 2.0 × as wide as long. Pronotum with a pair of conical, sclerotised, protuberances (p–pr) separated at bases. Meso- and metanotum similar in size. Abdominal segments I–VI almost identical in size; segment VII semicircular; segment VIII narrow with broad protuberances (a–pr); segment IX reduced. Urogomphi (ur) small, ending with sclerotised, sharp apexes (Fig. 62A–C).

Chaetotaxy. Well developed, setae medium to elongated, transparent. Head with one small os (Fig. 63A). Pronotum with two as, one ds, two ls, and four pls all medium in length. Dorsal parts of meso- and metathorax with two equal in length setae, placed medially. Apex of femora with a single elongated fes (Fig. 63A–C). Abdominal segments I–V with six setae dorsally, variable in length: first, second and fifth minute, third, fourth, and sixth medium, first placed anteromedially, the rest placed close to posterior margin of the segment. Abdominal segment VI with six setae dorsally, variable in length: first minute, second to sixth elongated, first placed anteromedially, second to sixth placed close to posterior margin of the segment. Abdominal segment VII with four elongated setae dorsally. Each lateral part of abdominal segments I–VII with two medium setae. Ventral parts of abdominal segments I–VIII with four setae (median pair robust, second to fourth short). Abdominal segment IX with two short setae ventrally (Fig. 63A–C).

This species is known from Spain, Portugal, southern France, Switzerland, and northwestern and central Italy (Alonso-Zarazaga et al. 2023). At the adult stage, due to the medium-large size and the broad subquadrate shape of the elytra, which are almost flattened on the disc, this species is similar to R. depressa (Rottenberg, 1872) and R. fuentei (Pic, 1906). From the former, with which it is also closely related phylogenetically, it can be mainly distinguished by the shape and the greater length of the rostrum and of the penis; from the latter, which belongs to the R. antirrhini group, it distinctly differs in the shape of the rostrum and obviously in the characters that easily distinguish the R. vestita group from the R. antirrhini group (femora strongly toothed, shape of the penis; Caldara et al. 2010).

The female usually oviposits 1–3 eggs per seed capsule. Egg hatching occurs 7–11 days after deposition. Larvae feed on seeds within capsules of Antirrhinum majus and A. latifolium Mill., consuming the majority of them. Pupation occurs within the seed capsule, and the emergence of the adults occurs ~ 20 days later. Adults exit the seed capsule by chewing through the hardened pericarp (IT and RC, pers. obs.).

11 mature and 5 premature larvae; 8 ♂ and 6 ♀ pupae. Serbia, Mokra Gora, ex Chaenorhinum minus (L.) Lange, 10.08.2017, leg., det. I. Toševski.

(Figs 64A, B, 65A–E, 66A–C). Measurements (in mm). Body length: 2.50–3.66 (avg. 2.83). The widest place in the body (meso- and metathorax) measures up to 1.16. Head width: 0.43–0.50 (avg. 0.46).

Figure 64. 

Rhinusa melas (Boheman, 1838) mature larva A habitus B head, frontal view.

Figure 65. 

Rhinusa melas (Boheman, 1838) mature larva, head and mouth parts A head B antenna C clypeus and labrum (left side), epipharynx (right side) D left mandible E maxillolabial complex (schemes). Abbreviations: at–antenna, lr–labral rods, sa–sensillum ampullaceum, Se–sensorium, st–stemmata, setae: als–anterolateral, ams–anteromedial, cls–clypeal, des–dorsal epicranial, dms–dorsal malar, fs–frontal epicranial, les–lateral epicranial, ligs–ligular, lrs–labral, mbs–malar basiventral, mds–mandibular dorsal, mes–medial, mpxs–maxillary palp, pes–postepicranial, pfs–palpiferal, pms–postmental, prms–premental, stps–stipital, ves–ventral, vms–ventral malar.

Figure 66. 

Rhinusa melas (Boheman, 1838) mature larva, habitus A lateral view of thoracic segments B lateral view of abdominal segment I C lateral view of abdominal segments VII–X (schemes). Abbreviations: Th. 1–3–number of thoracic segments, Abd. 1–10–number of abdominal seg, setae: as–alar, ds–dorsal, eps–epipleural, eus–eusternal, lsts–laterosternal, pda–pedal, pds–postdorsal, prns–pronotal, prs–prodorsal, ss–spiracular, ps–pleural, sts–sternal.

General. Body elongate, slender, moderately curved, rounded in cross section (Fig. 64A). All thoracic segments equal in size. Meso- and metathorax each divided dorsally into two folds (prodorsal fold very small, postdorsal fold prominent). Pedal folds of thoracic segments conical. Abdominal segments I–V of similar size, next segments tapering towards posterior body end. Abdominal segments I–VII each divided dorsally into two folds almost identical in size. Segments VIII and IX dorsally undivided. Epipleural folds of segments I–VIII conical. Laterosternal and eusternal folds of segments I–VIII conical, poorly isolated. Abdominal segment X divided into four folds of equal size. Anus situated ventrally, almost completely hidden in segment IX.

Thoracic spiracle bicameral, all abdominal spiracles unicameral; thoracic spiracle (Fig. 64A) placed laterally close to mesothorax; abdominal spiracles (Fig. 64A) placed medially on segments I–VIII.

Colouration. Light to dark yellow head (Fig. 64B). All thoracic and abdominal segments whitish (Fig. 64A). Cuticle covered with asperities.

Vestiture. Setae on body thin, transparent, different in length (minute to medium).

Head capsule (Figs 64B, 65A). Head suboval, endocarinal line present, reaching to 1/2 of the length of frons. Frontal sutures on head indistinct, very wide. Single pair of stemmata in the form of small dark spots (st) placed laterally, close to the end of the frontal suture. Des₁ short, located in middle part of epicranium; long des₂ located anteriorly; long des₃ placed almost on the border of the frontal suture; very short des₄ located laterally; very long des₅ placed anterolaterally above stemma (Fig. 65A). Fs₁ minute, placed posteriorly; fs₂ minute, located posterolaterally; fs₃ absent; fs₄ medium; and long fs₅ located anterolaterally, close to antenna (Fig. 65A). Les₁ medium and les₂ short; two short ves. Epicranial area with three pes.

Antennae placed distally of the frontal suture, on the inside; membranous and distinctly convex basal article bearing one conical elongate sensorium, plus two sensilla ampullacea (Fig. 65B).

Clypeus (Fig. 65C) trapezoidal, ~ 2.5 × as wide as long with two medium cls, localised posterolaterally, with one sensillum between them; anterior part distinctly less sclerotised than the basal part; anterior border slightly rounded towards the inside.

Mouth parts. Labrum (Fig. 65C) ~ 2.2 × as wide as long, with three piliform lrs, various long; lrs₁ and lrs₂ elongated, located medially, and lrs₃ medium, located anterolaterally; anterior border bi-sinuate. Epipharynx (Fig. 65C) with two elongated finger-like als, identical in length; two piliform ams variable in length, and single finger-like mes; labral rods (lr) distinct, kidney-shaped. Mandibles (Fig. 65D) bifid, cutting edge with small additional teeth; two medium piliform and short mds, both located close to lateral border. Maxillolabial complex: maxilla brownish sclerotised (Fig. 65E) stipes with one stps, two pfs and one very short mbs, stps and both pfs_1–2 elongated; mala with six finger-like dms variable in length; four medium piliform vms. Maxillary palpi two-segmented; basal palpomere distinctly wider than distal one; basal palpomere with short mpxs and two sensilla, distal palpomere with a group of four apical sensilla in terminal receptive area. Prementum (Fig. 65E) close to cup-shaped, with a single, medium prms; ligula with slightly sinuate margin and two short ligs; premental sclerite broad, sclerotised, posterior extension with elongated apex. Labial palpi one-segmented; palpi with a single pore, and four or five apical sensilla in terminal receptive area; surface of labium smooth. Postmentum (Fig. 65E) with three pms, medium pms₁ located posteromedially, long pms₂ located mediolaterally, and medium pms₃ located anterolaterally; membranous area partially covered with knobby asperities.

Thorax. Prothorax (Fig. 66A) with seven elongated and two medium prns; two medium ps; and single short eus. Mesothorax (Fig. 66A) with a single minute prs; three pds (ordered: minute, medium and medium); one medium as; two medium and one minute ss; one medium eps; one medium ps; and single minute eus. Chaetotaxy of metathorax (Fig. 66A) almost identical to that of mesothorax. Each pedal area of thoracic segments with four medium and single minute pda.

Abdomen. Segments I–VIII (Fig. 66B, C) with a single minute prs; three pds of various length; one minute and one medium ss; one medium and one minute eps; one medium ps; one medium lsts; and two minute eus. Abdominal segment IX (Fig. 66C) with two medium and one minute ds; one medium and one minute ps; and two minute sts.

(Figs 67A–C, 68A–C). Measurements (in mm). Body length: 2.30–2.90; body width: 0.80–1.75; thorax width: 0.90–1.05; rostrum length: up to 0.75 ♂ and ♀.

Figure 67. 

Rhinusa melas (Boheman, 1838) pupa habitus A ventral view B lateral view C dorsal view.

Figure 68. 

Rhinusa melas (Boheman, 1838) pupa habitus A ventral view B lateral view C dorsal view (schemes). Abbreviations: a–pr–abdominal protuberances, h–pr–head protuberances, p–pr–pronotal protuberances, ur–urogomphi, setae: as–apical, d–dorsal, ds–discal, fes–femoral, l, ls–lateral, os–orbital, pls–posterolateral, v–ventral.

Body. Integument white; moderately elongated. Head and pronotum with protuberances. Rostrum rather short, reaching to mesocoxae; on both sexes almost 2.2 × longer than wider. Pronotum trapezoidal 2 × as wide as long. Meso- and metanotum similar in size. Abdominal segments I–IV almost identical in size; segments V and VI tapering gradually, VII semicircular; segment VIII narrow; segment IX reduced. Abdominal segment VIII with, semicircular, weakly sclerotised abdominal protuberance (a–pr). Urogomphi vestigial, weakly sclerotised (Fig. 67A–C).

Chaetotaxy. Well-developed setae, elongated to short, dark brown. Head with a single short os. Rostrum without seta (Fig. 68A). Pronotum with a single as, single ds, four ls, and three pls; all pronotal setae elongated, equal in length. Dorsal parts of meso- and metathorax with two elongated setae, placed medially (Fig. 68A–C). Abdominal segments I–VIII dorsally with three medium (on segments VII and VIII elongated) setae dorsally, placed close to posterior margin of the segments. Each lateral part of abdominal segments I–VIII with one short seta. Ventral parts of abdominal segments I–VIII with three short setae, of which medial are robust, almost thorn-like. Abdominal segment IX without seta ventrally (Fig. 68A–C).

This species is widely distributed, although uncommon, in southern, western, and central Europe (Alonso-Zarazaga et al. 2023). The apparent presence only in southern Spain and in the Pyrenees of adults of a form with a reddish elytral integument together with specimens with black elytra is unusual, although not unique in the genus Rhinusa. In fact, the same occurs in R. bipustulata (Rossi, 1792) and R. tetra, which live on Scrophularia and Verbascum and are unrelated to R. melas. It will surely be very interesting to confirm this distributional pattern through a molecular study.

The host plant of R. melas is Chaenorhinum minus. Larvae develop in the seed capsules, where they pupate (Hoffmann 1958; Smreczyński 1976). Adults were also collected on Linaria vulgaris, L. repens and L. spartea, but most likely as occasional visitors.