A revision of the Australian digger wasps in the genus Sphex (Hymenoptera, Sphecidae)

Abstract The Australian species of the sphecid wasp genus Sphex are revised. Thirty-five species are recognized, of which 11 are new: Sphex argentatissimus, Sphex brevipetiolus, Sphex caelebs, Sphex corporosus, Sphex flammeus, Sphex fortunatus, Sphex gracilis, Sphex imporcatus, Sphex jucundus, Sphex latilobus and Sphex pretiosus. A dichotomous key covering all Australian species of the genus has been generated. The geographic distribution of all species is discussed based on all available locality records in relation to the Australian climate zones.

Most species of Sphex are gregarious and nest in large groups of several individuals. Ground nests contain 3-10 separate cells which are built in side branches of the main tunnel, usually approximately 10-15 cm deep, but sometimes deeper depending on species and soil type (Kazenas 2001). Females travel up to 2.5 km from the nest when searching for prey (Kazenas 2001). The number of prey items per cell varies from 3 or 4 to 6 or 7. Many species prey on tettigoniids, a few on gryllacridids and some on gryllids (Bohart and Menke 1976;Evans et al. 1982;Kazenas 2001).
The number of valid Australian species ranges from 24 (Cardale 1985) to 26 (Pulawski 2014). The aim of this study is to revise the genus in Australia. The revision includes an up-to-date dichotomous key for all species.
In the past, several authors focused on the taxonomy of Sphex, the most important publications being F. Smith (1856Smith ( , 1859Smith ( , 1868, F. F. Kohl (1890Kohl ( , 1895, R. E. Turner (1908Turner ( , 1910Turner ( , 1910Turner ( , 1912Turner ( , 1915, J. van der Vecht (1955van der Vecht ( , 1957 and R. V. Hensen (1991). Keys were published, which, among others, included 14 species (Kohl 1890), 16 species (Turner 1910) and 8 species (Hensen 1991) of Sphex which were known or assumed to be Australian. However, all of these works are outdated or at least of limited value. Most of the species descriptions by Frederick Smith do not contain sufficient information to distinguish unequivocally the species within the genus, and some of the length ratios given by Kohl seem to be inaccurate. Turner's (1910) key covers only females, some of which he apparently did not examine personally, and Hensen (1991) focuses on the Malesian Sphecinae, addressing the Australian fauna only partially.
In this study, all previously described species of Sphex from Australia were examined, and all 24 species native to Australia based on Cardale (1985) are redescribed. Additionally, 11 new species from Australia are described.

Sources of material
The material used in this study comes from the following institutions. Abbreviations of institution names mostly follow Pulawski (2014). All individuals are pinned.

Technical devices and programs
A stereoscopic microscope Leica MZ12 and a light source Leica KL 1500 LCD were used for optical examination. The measurements were done with an ocular micrometer. Photographs of whole insects or different body parts were taken with a Canon EOS 400D Digital camera and a Canon Macro Ring Lite MR-14EX flash device. Detailed multi-focus photographs of the diagnostic characters were taken with a Leica DFC 490 Digital camera on a Leica Z16Apo stereoscopic microscope using Leica Application Suite Version 4.5.0 and merged with Helicon Focus 5.3.14.
The digital drawings were produced with the use of a graphical tablet (Wacom Intuos5 Touch M), Adobe Photoshop CS4 (Version 11.0.2) and Adobe Illustrator CS4 (Version 14.0.0), as described by Coleman (2003).
The species key was generated using DELTA (Version 1.02). All maps were created with QGIS (Version 2.0.1-Dufour) and the use of Google Earth (Version 7.1.2.2041). The political map of Australia was downloaded from www.naturalearthdata.com.
Images were edited and cleaned of dirt using Adobe Photoshop CS6, Version 13.0.1 and Adobe Illustrator CS6, Version 16.0.1.
The "material examined" section was formatted using the AutoMatEx spreadsheet (Brown 2013) and Microsoft Excel 2010.

Diagnosis of Sphex
Sphex differs from the closely related Isodontia in the length of the petiole and the ratio between the anterior and the posterobasal veinlet of submarginal cell III. Sphex has a petiole that is shorter than the combined lengths of hindtarsomeres II-IV, while in most Isodontia the petiole is equal to or longer than the hindtarsomeres II-IV combined. The anterior veinlet is usually shorter than the posterobasal in Sphex, but conspicuously longer than it in Isodontia. The nominate subgenus Sphex (Sphex) shares the former of these two characters with the subgenus Sphex (Fernaldina), which comprise two Old World species only, and the anterior veinlet can be shorter or equal to the posterobasal one in Sphex (Fernaldina). Nonetheless, the fact that a complete spiracular groove is only present in Sphex (Sphex) differentiates this genus from Isodontia (Bohart and Menke 1976;Ohl 1996).

Sexual dimorphism in Sphex
Several characters that are diagnostic for species of Sphex are strongly sexually dimorphic. Most of these characters are listed for Sphecidae sensu stricto (Pulawski 2014) by Bohart and Menke (1976;as Sphecinae), but a few are not mentioned there. The most important characters are covered in the following paragraph.
In general, males are more extensively black and have paler wings than females (Bohart and Menke 1976). They also tend to have denser pubescence on the mesosoma and especially on the sterna of the metasoma.
Males often lack the conspicuous structures on the free clypeal margin that many females possess. Although there are a few species in which the male clypeal margin carries lobes, it is mostly truncate and entire. These differences are presumably affiliated with the female life style (see below).
The scutellar morphology is also often sexually dimorphic. It is commonly convex and medially impressed in males, whereas most females have a scutellum that is flatter and lacks impressions.
Finally, the apical metasomal sternum of females lacks diagnostic features almost entirely, but that of males is an important character for species delimitation.

General remarks
Many of the specimens examined show effects of abrasion. The following characters, which appear to be diagnostic, are especially affected: clypeal lobes, pubescence on all parts of the body, and the female foretarsal rake. Females seem to be more prone to this effect, apparently as a result of the nest digging.
Localities outside of Australia and those of specimens which could not be reliably determined were not included in the maps. Localities of Australian specimens that have not been examined in this study were included if they appear to be plausibly within the known range of the species.
Within each species group, the species are arranged alphabetically. Locality records in the "Material examined" section are arranged in the following sequence under each state: unspecified localities are listed first, very imprecise records are listed after that, and finally localites in alphabetical order. Records that begin with information about a specific distance or direction are listed at the respective locations that they use as reference.

Notes regarding descriptions and key to species
The classification of the species in this paper follows Hensen (1991) in his subdivision of the Malesian and Australian species of the genus into three species-groups, the Sphex argentatus, Sphex resplendens and Sphex subtruncatus species groups. All species from Australia can be readily assigned to one of the groups.
The measurements of the petiole were done from above from the center of the joint at the posterior end of the propodeum to the anterior margin of tergum I (Fig. 7). The morphological nomenclature was taken from Bohart and Menke (1976).
Termini for describing bristles are used in this work in the following manner: Very short, fine and usually appressed ones with a moderate to high density are called "tomentum"; they are found mostly on the metasomal terga of the wasp. The term "pubescence" is applied when characterizing bristles that cover a larger area like the face or the propodeal enclosure. They are considerably longer than those in the tomentum, can be appressed or erect, and vary between low and very high density. Finally, "setae" describe smaller groups of bristles that are isolated in some way, either literally by forming fringes or figuratively by being differently colored than the surrounding pubescence, the latter of which is often the case on the clypeus. Setae are usually long and erect.
For each species, only synonyms which are relevant for the currently valid name of the respective species are listed, or which are referred to in the descriptions. The complete lists of synonyms of all species can be found in Pulawski (2014). Twelve species are known from one sex only. The unknown females of S. caelebs, S. fortunatus, S. latilobus and S. semifossulatus as well as the unknown males of S. ahasverus, S. brevipetiolus, S. darwiniensis, S. decoratus, S. flammeus, S. gilberti, S. imporcatus and S. rhodosoma are not included in the key.    2H), with appressed silvery-white pubescence ( Fig. 6A-C, E); free clypeal margin without lobes (Fig. 6A) 6D); pubescence on propodeal enclosure completely concealing sculpture (Fig. 5A, B) ..........S. ermineus Kohl 64(59) Petiole longer than flagellomere II; pubescence on propodeal enclosure golden (Fig. 5D); wing membrane at least partially with yellow tinge in cellular wing area (Fig. 2D)

Species group of Sphex argentatus
Australian species of this group are characterized by a markedly raised metanotum in conjunction with a longitudinal median impression of varying depth and width (Hensen 1991). In this paper, the resulting paired elevations are called tubercles, and the depth of the impression between them can be used to furthermore differentiate between the group members. It should be noted, however, that for species with an only inconspicuosuly raised metanotum, the presence of a longitudinal impression on it was considered to be insufficient as a single character for the species group assignment. Species with this combination of features have been assigned to species groups based on their observed intraspecific variation. Currently, there are six Australian species in this group.
Since the other attributes mentioned by Hensen (1991) in his diagnosis of the S. argentatus group are also present in at least some species from the other two groups like a convex and medially impressed scutellum, placoids on the male antenna (see also diagnosis of S. resplendens group) or are diagnostic for the entire genus (like a bidentate mandible) they have been largely ignored in the delimitation of the species groups. The characters of the metanotum have been found to be sufficient for this. Description. Body black. Base of fore-and hindwing membrane darkened, forewing with fuscous spot beyond marginal cell. Wing veins brown to black. Appressed pubescence and erect setae on clypeus and frons silvery-white, no medial glabrous stripe on clypeus. Pubescence on collar and scutum silvery, on scutum slightly denser laterally than medially. Tubercles on metanotum distinct. Propodeal enclosure with thin, erect silvery setae, leaving sculpture well visible.

Sphex argentatus
Female: Body length 21.6-32.4 mm. Forebasitarsal rake with 10 long spines. Free clypeal margin with two inconspicuous lobes medially, distance between them less than 1/8 length of flagellomere II. Distance between hind-ocelli 0.8× their shortest distance to compound eyes. Scutellum flat, with shallow medial impression near posterior margin. Length of petiole 1.4× length of flagellomere II. Tomentum sparse on metasomal tergum I, absent on tergum II.
Male: Body length 23.8-26.2 mm. Free clypeal margin truncate, slightly concave toward center, with short median lobe. Distance between hind-ocelli 1.4× their shortest distance to compound eyes. Scutellum convex, with shallow medial impression. Length of petiole 1.65× length of flagellomere II. Tomentum moderately dense on metasomal tergum I and II. Metasomal tergum V with only a few, tergum VI with considerable number of black setae. Metasomal sternum VII with large fringe of dark setae laterally, sterna anterior of it each with a lesser amount of setae. Metasomal sternum VIII entire, its lateral margin straight.
Notes on type material. The types of S. argentatus and its synonyms were not examined, because of the character combination in the redescription of the species by Kohl (1890) (as S. umbrosus, synonymized with S. argentatus by van der Vecht (1961(as S. umbrosus, synonymized with S. argentatus by van der Vecht ( , 1973: black body, bituberculate metanotum, uniformly silvery pubescence on face, sculpture on propodeal dorsum visible through moderately dense pubescence) is sufficient to unambiguously identify this species.  wings except for a slight brown tinge at the apical margin of the forewing in some specimens. Specimens of Sphex sericeus that may have the same color pattern are identifiable by the conspicuous transverse ridges on their propodeum, which are lacking in S. carbonicolor. Sphex argentatus and Sphex finschii have a darkened wing base, while Sphex decoratus differs by having orange legs (which are dark brown or black in S. carbonicolor).

Sphex carbonicolor van der
Description. Body length 27.6-35.6 mm. Body black. Wing membrane hyaline, forewing with fuscous spot beyond marginal cell. Wing veins brown. Clypeus bulging directly above free margin. Appressed pubescence and erect setae on clypeus and frons silvery. Clypeus with medial glabrous stripe. Distance between hind-ocelli nearly equal to their shortest distance to compound eyes. Pubescence on collar and scutum silvery, on scutum denser laterally than medially. Scutellum slightly convex, with medial impression. Tubercles on metanotum distinct. Propodeal enclosure densely covered with long, erect silvery-white setae, leaving sculpture visible. Length of petiole 1.1× length of flagellomere II. Tomentum moderately dense on metasomal tergum I and II, but very short.
Female: Foretarsal rake with 12 long spines. Free clypeal margin with small notch medially.
Notes on type material. The type of S. carbonicolor was not examined, because the character combination listed in the original description (black body, a glabrous area on the clypeus, a bituberculate metanotum, hyaline wings) is almost unique. Sphex ephippium, which shares these features, is sufficiently differentiated by its character combination (see below).
Material examined. Holotype (presumed). ♀, AUSTRALIA: WA: "NW Coast", (BMNH). Other material. AUSTRALIA: QLD: "North Queensland", 1♀, (BMNH). Diagnosis. Sphex decoratus (of which only the female is known) can be recognized by the combination of markedly raised, distinct tubercles on the metanotum, a mostly orange metasoma of which segment II is black, and a plain propodeal surface. Sphex sericeus greatly varies in color and may look superficially similar to S. decoratus, but differs in having a markedly ridged propodeal dorsum, whereas that of S. decoratus lacks notable ridges. Description. Female: Body length 24.6-27.2 mm. Body black, but the following are orange: base of mandible, clypeus, scape, pedicel, flagellomere I, flagellomere II-IV above, tegula, subalar area, pronotal lobe, area below anteroventral metapleural pit, petiole, at least parts of metasomal segments I and IV-VI, legs except for base of coxa as well as claw teeth and distal half of claw. Wing membrane yellow near base, hyaline at apex. Wing veins bright orange. Forebasitarsal rake with 11 long spines. Free clypeal margin plain or with insignificant emarginations. Appressed pubescence and erect setae on clypeus and frons golden. Clypeus glabrous medioventrally. Distance between hind-ocelli slightly smaller than their shortest distance to compound eyes. Pubescence on collar and scutum golden, the latter with longer, denser pubescence laterally and posteriorly. Scutellum convex, with distinct medial impression. Tubercles on metanotum distinct. Propodeal enclosure with dense, appressed golden pubescence and sparse, erect golden setae; sculpture completely concealed. Length of petiole twice length of flagellomere II.
Male: Unknown. Notes on type material. In the original description, F. Smith did not mention the sex of the holotype. It is listed as a male by Pulawski (2014). However, examination of the type shows that it is clearly a female.
Geographic distribution. Only two specimens of S. decoratus could be studied, and no specific geographic information is available. The origin of the holotype is given as 'northwest coast of Australia' in the original description, that of the other examined specimen as 'North Queensland'.

Sphex ephippium F. Smith, 1856
Sphex ephippium F. Smith  Diagnosis. Sphex ephippium is unique in the combination of a tuberculate metanotum, appressed golden pubescence on the clypeus interspersed with longer dark setae, and long, silvery-white pubescence concealing the sculpture of the propodeal enclosure.
Description. Body black. Wing membrane darkened at base, with fuscous band at apex. Wing veins dark brown. Appressed pubescence on clypeus and frons golden, erect setae on clypeus black and on frons golden. Clypeus with medial glabrous stripe. Pubescence on collar and scutum silvery, denser laterally and posteriorly on latter. Scutellum convex. Metanotum markedly raised, tubercles indistinct. Propodeal enclosure densely covered with long, silvery-white pubescence aligned anteriorly, mostly concealing sculpture. Tomentum moderately dense on metasomal tergum I and II.
Female: Body length 22.8-30.6 mm. Free clypeal margin slightly scoop-shaped, with indistinct emarginations. Distance between hind-ocelli slightly smaller than their shortest distance to compound eyes. Forebasitarsal rake with nine long spines. Scutellum without impression. Length of petiole 1.7× length of flagellomere II. Tomentum absent on apical half of metasomal tergum II.
Male: Body length 21.2-24.6 mm. Free clypeal margin truncate, concave towards center. Distance between hind-ocelli 1.15× their shortest distance to compound eyes. Scutellum with or without medial impression. Length of petiole almost twice length of flagellomere II. Metasomal terga V and VI covered with black bristles. Metasomal sterna II-V with a few erect black setae, VI-VIII more densely covered with silvery setae and brown ones with silvery tips. Metasomal sternum VIII entire, its lateral margin straight.
Notes on type material. The type of S. ephippium was not examined, because the character combination in the original description (darker setae among the golden pubescence of the face, dense silvery pubescence on propodeal enclosure) is sufficient to unambiguously identify this species. Diagnosis. This species is well characterized by its wings, which are largely hyaline but darkened at the base. It shares this trait with three other species. One of them is Sphex luctuosus that can be distinguished by claw teeth perpendicularly oriented to the inner margin of the claw, a character of the S. resplendens group (as a member of the S. argentatus group, S. finschii possesses obliquely oriented claw teeth). The second spe-cies, Sphex argentatus, is identifiable by its distinctly tuberculate metanotum, while the tubercles are indistinct in S. finschii. The third species, Sphex fortunatus, has erect setae that are uniformly silvery on its clypeus, whereas S. finschii has black setae.

Sphex finschii
Description. Body black. Costal cell of fore-and hindwing dark. Base of forewing membrane darkened, sometimes up to the medial cell's distal margin, fuscous band at apex. Hindwing membrane darkened mainly near base. Wing veins dark brown to black. Appressed pubescence on clypeus and frons silvery, erect setae on clypeus black and on frons silvery. Clypeus with glabrous ridge dorsomedially. Pubescence on mesosoma silvery, denser laterally on scutum. Scutellum convex, with shallow medial impression. Metanotum markedly raised, tubercles indistinct. Pubescence on propodeal enclosure sparse and fine, leaving sculpture fully visible. Length of petiole nearly 1.7× length of flagellomere II. Tomentum moderately dense on metasomal tergum II.
Female: Body length 21.6-29.2 mm. Forebasitarsal rake with nine long spines. Free clypeal margin with 3 faint lobes medially, distance between them less than 1/8 length of flagellomere II. Distance between hind-ocelli 0.9× their shortest distance to compound eyes. Tomentum moderately dense on metasomal tergum I.
Male: Body length 20.4-25.2 mm. Free clypeal margin truncate, concave medially. Area adjacent to it glabrous. Distance between hind-ocelli 1.1× their shortest distance to compound eyes. Tomentum dense on metasomal tergum I. Metasomal terga V and VI with few black bristles. Metasomal sterna II-IV mostly glabrous, V-VII with increasingly dense fringes of dark and silvery setae laterally on apical margin. Metasomal sternum VIII entire, covered with silvery pubescence, its lateral margin straight.
Geographic distribution. Although S. finschii is listed by Cardale (1985) and Hensen (1991), no specimen was found that has actually been collected in Australia. Individuals examined during this study come from New Guinea, the Solomon Islands, or Indonesia.
Holotype or syntypes: ♀, Australia: no specific locality (BMNH  Diagnosis. Sphex modestus is unique among the Australian Sphex in the combination of the following characteristics: claw teeth obliquely oriented to inner claw margin, wing membrane with a yellow tinge towards their base, appressed pubescence on clypeus silvery-white interspersed with erect black setae, legs and metasoma entirely black or dark brown, and propodeal enclosure not concealing sculpture. Sphex pretiosus is superficially similar, but, among other things, the color of its erect setae on the clypeus matches that of the silvery and silvery-golden appressed pubescence, whereas the erect setae on the clypeus of S. modestus are black. Description. Body black. Forewing membrane dark at the very base (Fig. 13B), with yellow tinge in basal half, remainder hyaline and with fuscous band at apex. Wing veins orange, dark brown near very base and around marginal cell of forewing. Clypeus with medial glabrous stripe. Appressed pubescence on clypeus and frons silvery, erect setae on clypeus black and on frons silvery. Pubescence on collar, scutum, scutellum and metanotum silvery, on scutum denser laterally and posteriorly. Scutellum convex, with medial impression. Tubercles on metanotum indistinct. Pubescence on propodeal enclosure silvery-white to dirty beige, not completely concealing sculpture. Length of petiole 1.8× length of flagellomere II.
Female: Body length 19.6-24.6 mm. Forebasitarsal rake with 10 long spines. Free clypeal margin with two faint lobes medially, distance between them less than 1/8 length of flagellomere II. Distance between hind-ocelli 1.25× their shortest distance to compound eyes. Tomentum sparse on metasomal tergum I, absent on tergum II.
Notes on type material. The type of S. modestus F. Smith, 1856 was not examined, but we did study the type of S. bannitus Kohl, 1890, which was synonymized with S. modestus by R. Turner (1910 Diagnosis. Sphex sericeus is unique among its Australian congeners in having three to four broad, continuous transverse ridges on the propodeal enclosure which are even visible through the pubescence. Female specimens of Sphex rugifer, Sphex darwiniensis and Sphex imporcatus possess vaguely similar structures, but those are much finer. S. rugifer also has approximately 20 ridges on the propodeal enclosure, while those of S. darwiniensis and S. imporcatus are discontinuous in the center.
Description. Clypeus with medial glabrous stripe. Pubescence on scutum slightly denser laterally. Scutellum slightly convex, with shallow medial impression near posterior margin. Tubercles on metanotum distinct. Propodeal enclosure with three to four broad, continuous transverse ridges; propodeal pubescence not concealing sculpture. Tomentum moderately dense on metasomal terga I and II.
Female: Body length 20.2-25.7 mm. Body black, but the following are orange: basal half of mandible, clypeus, scape, pedicel, parts of flagellomere I, scutellum, metanotum, petiole, metasomal segment I, anterior two thirds of metasomal segment II, legs excluding claw teeth and distal half of claw. Wing membrane with yellow tinge and markedly fuscous band at apex. Wing veins orange, dark near apex. Forebasitarsal rake with nine long spines. Free clypeal margin conspicuously notched medially, bulging above. Appressed pubescence and erect setae on clypeus and frons golden. Distance between hind-ocelli 0.7× their shortest distance to compound eyes. Pubescence on mesosoma golden. Length of petiole 1.4× length of flagellomere II.
Male: Body length 16.8-23.6 mm. Wing membrane largely hyaline, with slight yellow tinge around costal cell. Forewing with faint fuscous band at apex. Wing veins dark brown to orange. Free clypeal margin concave towards center. Appressed pubescence and erect setae on clypeus and frons silvery-white. Distance between hind-ocelli nearly equal to their shortest distance to compound eyes. Pubescence on mesosoma silvery. Length of petiole 1.6×-1.7× length of flagellomere II. Metasomal terga V and VI with few silvery bristles. Metasomal sterna II-VIII largely glabrous. Metasomal sternum VIII entire, its lateral margin sometimes slightly concave. Variation. Males of this species markedly vary in color, though most Australian specimens belong to either one of two forms: the first form has the following parts bright red: anterior side of midfemur, entire hindfemur, petiole, metasomal segments I and II (Fig. 14B), while the body of the second form is entirely black (Fig. 14C). The color of the females seems to be more or less uniform among the collecting localities.
Notes on type material. The types of S. sericeus and its synonyms were not examined, because the character combination in the redescription by Kohl (1890) (broad transverse ridges on propodeal enclosure, bituberculate metanotum) is sufficient to unambiguously identify this species. Van der Vecht (1961) noted that the lectotype of this species agrees with the species current (i.e., Kohl's) interpretation.

Species group of Sphex resplendens
This group currently contains ten species, including two new ones described in this paper. In accordance with Hensen (1991), species of this group have the distal claw teeth oriented perpendicularly to the claw, specifically to the point where the claw tooth emerges. In contrast, all species of the S. argentatus and the S. subtruncatus group possess claw teeth oriented obliquely to the claw. There are only few specimens where the orientation of the claw teeth is ambiguous, and most of these cases can probably be attributed to the effects of deterioration during the wasps' lives.
There are a few other characters which are often found in species of the S. resplendens group, like a conspicuously flat and shining scutellum without impressions in the female. However, these traits are not universal for all members and also exist in a few species that, based on the alignment of their claw teeth, clearly belong in one of the other groups. Another feature Hensen (1991) cited in his diagnosis of the group was the absence of antennal placoids in males, but this was found out not to be a universal characteristic among the members. Rather, placoids are often only less distinct in these species, which makes a differentiation difficult. Therefore, attributes other than the alignment of the claw teeth have been given less importance for species group determination than in Hensen's key (1991).
Material examined. Holotype (presumed). ♀, AUSTRALIA: NT: Port Darwin, 1911, F. P. Dodd (BMNH). The collecting locality is shown in Fig. 20B. Diagnosis. Sphex darwiniensis (of which only the female is known) differs from all other Australian Sphex in having the features diagnostic for the S. resplendens group combined with orange legs and metasoma, partly yellowish wings and approximately ten distinct, fine transverse ridges on the propodeal enclosure. The similar Sphex rugifer has a uniformly dark forewing, black legs and a black petiole. Sphex rhodosoma, in contrast to both the former species, is almost completely orange, including the entire mesosoma.
Description. Female: Body length 22.2 mm. Body black, but the following are orange: apical half of mandible, clypeus, scape, pedicel, base of flagellomere I, legs from trochanter onward except for claw teeth and apical half of claw, tegula, subalar area, petiole, gaster. Wing membrane yellow, darkened beyond submarginal cell I. Wing veins orange, brown in darkened area of wing. Forebasitarsal rake with seven long spines. Free clypeal margin medially with two lobes which are slightly convex above, distance between them less than 1/8 length of flagellomere II. Appressed pubescence and erect setae on clypeus and frons silvery-white. Clypeus with medial glabrous stripe. Distance between hind-ocelli slightly smaller than their shortest distance to compound eyes. Pubescence on collar and scutum silvery-white, the latter glabrous except laterally and posteriorly. Scutellum flat, shiny, without impressions. Propodeal enclosure with short, silvery-white pubescence and approximately ten distinct transverse ridges which are in-terrupted medially, sculpture almost completely visible. Length of petiole approximately 0.9× length of flagellomere II. Tomentum on metasomal terga I and II sparse and short.

Sphex fumipennis F. Smith, 1856
Sphex fumipennis F. Smith, 1856: 249, ♀, ♂. Syntypes: Australia: South Australia: Adelaide (BMNH). One syntype examined. Diagnosis. Sphex fumipennis is distinguished from almost all other Australian Sphex in having largely dark wings, a black metasoma and silvery-white pubescence on the propodeal enclosure. There is only one other species with similar features, Sphex rugifer, and while most females of this species have a red metasoma, the males as well as some females have a black metasoma like S. fumipennis. A reliable characteristic of S. fumipennis is that the hindwing becomes almost completely hyaline towards the apical margin (Fig. 16B), while that of S. rugifer is, at least in the distal half, uniformly dark ( Fig. 24A-C). Males of S. fumipennis also have a conspicuous fringe of silvery setae near the apex of metasomal sternum VIII (Fig. 16C), whereas males of S. rugifer lack this pubescence (Fig. 24D).
Description. Body black, legs black or maroon. Wing membrane dark, with violet lustre near base, apical margin of forewing membrane and distal part beyond cellular area of hindwing membrane hyaline. Wing veins dark brown to black. Appressed pubescence on clypeus and frons silvery, erect setae on clypeus and frons black. Pubescence on top of collar silvery, long lateral setae black. Pubescence on scutum silvery, interspersed with few black setae near anterior margin. Silvery pubescence on scutum denser laterally. Propodeal enclosure sparsely covered with silvery-white pubescence, leaving sculpture completely visible. Posterior end of propodeum with black setae.
Female: 22.2-28.4 mm. Forebasitarsal rake with eight long spines. Free clypeal margin slightly scoop-shaped, with two distinct lobes medially and small bulge slightly above them; distance between lobes less than 1/8 length of flagellomere II. Clypeus except for bulge entirely pubescent. Distance between hind-ocelli nearly equal to their shortest distance to compound eyes. Scutellum flat, without impressions. Length of petiole almost equal to flagellomere II. Tomentum sparse on metasomal tergum I, absent on tergum II.
Male: Body length 15.2-21.2 mm. Free clypeal margin truncate, concave towards center. Medioventral part of clypeus glabrous. Distance between hind-ocelli 1.25× their shortest distance to compound eyes. Scutellum convex, with (sometimes shallow) medial impression. Length of petiole 1.25× length of flagellomere II. Tomentum moderately dense on metasomal terga I and II. Metasomal terga V and VI with a few black bristles. Metasomal sterna II-VI with few appressed silvery setae, sterna VII with several erect black setae, sternum VIII with a dense fringe of silvery setae in center. Metasomal sternum VIII entire, raised from side to center, its margin straight.

Sphex gilberti R. Turner, 1908
Sphex gilberti R. Turner, 1908: 468 The collecting localities are shown in Fig. 24E. Diagnosis. This species (of which only the female is known) is characterized by a black metasoma with a dark blue lustre, extensively yellow wings, and dark pubescence on scutum and propodeal enclosure. Sphex resplendens, which is otherwise similar, has uniformly dark wings. The pubescence on the propodeal enclosure of Sphex modestus is at least partially silvery or yellowish, and its hindwing membrane is missing the yellow tinge. Sphex modestus is also distinguished by the presence of tubercles on its metanotum, even though sometimes they are only faintly recognizable, while in S. gilberti the metanotum is plain.
Description. Female: Body length 22.4-26.8 mm. Body black, legs brown. Wing membrane yellow, with slightly fuscous band at apex. Wing veins orange to light brown. Forebasitarsal rake with eigtht long spines. Free clypeal margin medially with two lobes which are separated only by a small notch. Appressed pubescence on clypeus and frons silvery, erect setae black. Clypeus with conspicuous indentation medioventrally and vertical glabrous stripe dorsoventrally. Distance between hind-ocelli approximately 0.6× their shortest distances to compound eyes. Pubescence on collar silvery. Scutum with sparse, erect, black setae and denser, silvery-white setae laterally. Scutellum slightly convex, without impressions. Propodeal enclosure with sparse, erect black pubescence, sculpture completely visible. Length of petiole almost equal to flagellomere II. Tomentum moderately dense on metasomal tergum I, sparse on tergum II.
Male: Unknown. Diagnosis. This species differs from other Australian Sphex of the S. resplendens group in having a combination of the following features: erect setae on clypeus uniformly silvery-white, metasoma black, and clypeal surface without wrinkles. Further- Figure 18. Sphex gracilis. A ♀, habitus B ♂, habitus C ♂ with brown wing veins and without yellow tinge on wings D ♂ with orange wing veins and a yellow tinge on wings E collecting localities, the combined symbol indicates that males and females were found in the same locality. more, the metasoma of female S. gracilis is considerably slenderer than that of other examined species (Fig. 18A).
Description. Body black. Wing membrane hyaline, with fuscous band at apex. Wing veins orange to light brown. Appressed pubescence and erect setae on clypeus and frons silvery. Pubescence on mesosoma silvery-white. Scutellum with shallow medial impression. Pubescence on propodeal enclosure short and sparse, leaving sculpture easily visible.
Female: Body length 19.9-25.9 mm. Mandible basally and ventral part of clypeus reddish, distal tarsomeres sometimes inconspicuously orange. Wing veins darker near apex. Forebasitarsal rake with 5-8 spines which are markedly short and stout. Free clypeal margin faintly convex medially. Clypeus mostly glabrous, only laterally with pubescence. Distance between hind-ocelli equal to their shortest distance to compound eyes. Pubescence on scutum denser laterally and posteriorly. Scutellum flat. Length of petiole nearly equal to flagellomere II. Tomentum very sparse on metasomal tergum I, absent on tergum II.
Male: Body length 18.5-20.6 mm. Forewing membrane sometimes with yellow tinge, hindwing membrane entirely hyaline. Wing veins light brown, sometimes orange, often darker near apex, sometimes uniformly colored. Free clypeal margin simple, concave towards center. Clypeus with narrow medial glabrous stripe , ventral part also glabrous. Distance between hind-ocelli 0.9× their shortest distance to compound eyes. Pubescence on scutum denser laterally. Scutellum convex. Length of petiole 1.4× length of flagellomere II. Tomentum dense on metasomal tergum I, moderately dense on tergum II. Metasomal tergum V and VI with few bristles. Metasomal sterna II-VI mostly glabrous, apical margin of metasomal sternum VII and VIII covered with silvery pubescence. Metasomal sternum VIII entire, its lateral margin inconspicuously concave.
Discussion. At first, the males and females of this species look quite different. While the habitus of the male matches that of most examined species of Sphex, the female's metasoma is much slenderer and seems longer than that of other species. Nonetheless, they most likely are the same species, as indicated by the following features.
One of the most important characters that connect both sexes is the uniformly silvery pubescence on the clypeus. In at least six of the ten other Australian species in the S. resplendens group, the erect setae on the clypeus are black. Of the remaining four species, two are colored bright orange. One of the other two has extremely unusual structures on the clypeal surface. Concerning the last remaining species other than S. gracilis, male and female individuals were found that have both silvery and golden pubescence on the clypeus as well as on the propodeum, a unique trait among the studied material.
Moreover, this is also the only species in the S. resplendens group where some males and females (see below for explanation) have the wing membrane entirely hyaline (excluding the apical margin), even at the base, and without any yellow. Both also have a very similar sculpture on the propodeal enclosure, and they also share the same length, density and orientation of its pubescence. Finally, the collecting localities show that both sexes occur in close proximity (Fig. 18E).
There seems to be some variability among individuals, but they are nonetheless presumed to be of a single species. In both sexes, there are specimens that come from the same collecting series and are distinctively different in their wing coloration. One group possesses brown wing veins and wings that have no hint of yellow (Fig. 18C), the other group has orange wing veins and (in males) a yellow tinge in the basal half of the forewing membrane (Fig. 18D).
Etymology. Gracilis is a Latin adjective meaning "slender". It refers to the habitus of the female metasoma. The collecting localities are shown in Fig. 23B. Diagnosis. Sphex imporcatus (of which only the female is known) is unique among Australian Sphex in having a remarkably modified clypeus (Fig. 4E, 19B). Dorsomedially on the clypeus, there is a deep groove of which the lower rim is encompassed by 5-8 markedly arcuate, broad wrinkles that almost reach the free clypeal margin. Furthermore, S. imporcatus possesses several distinct transverse ridges on the propodeum, a characteristic it only shares with Sphex sericeus, Sphex darwiniensis and Sphex rugifer. Sphex sericeus, as a member of the S. argentatus group, is set apart by having a pair of distinct tubercles on the metanotum and a partially ferruginous metasoma, while the metanotum of S. imporcatus lacks tubercles and its metasoma is black. The metasoma of S. darwiniensis is bright ferruginous, and S. rugifer can be distinguished by having fuscous wings, whereas Sphex imporcatus has hyaline wings with a slight yellow tinge.
Description. Female: Body length 24.3-25.6 mm. Body black except for tarsomeres V, which are at least partly orange, and also base of mandible and ventral part of clypeus and the wrinkles on it, which range from orange to maroon. Forewing membrane with yellow tinge on basal half and a slightly fuscous band at apex, hindwing membrane slightly yellowish near base. Wing veins bright orange, almost yellow. Forebasitarsal rake with 6-7 spines which are markedly short and stout. Free clypeal margin inconspicuously notched medially. Clypeus dorsomedially with deep groove of which the lower end is encompassed by 5-8 markedly arcuate, broad wrinkles that almost reach the free clypeal margin. Appressed pubescence and erect setae on clypeus and frons silvery-white. Clypeus with medial glabrous stripe. Distance between hindocelli 0.9× their shortest distance to compound eyes. Pubescence on collar, scutum, metanotum and propodeal enclosure silvery-white, scutum glabrous except laterally and posteriorly. Scutellum flat, without impressions. Propodeal enclosure with 6-9 discontinuous transverse ridges, pubescence not completely concealing sculpture. Length of petiole 1.15× length of flagellomere II. Tomentum very sparse, on metasomal tergum I only present near center, absent on tergum II.
Male: Unknown. Discussion. All three available specimens were heavily deteriorated, seemingly by abrasion. It is unknown whether the lesser length of the spines in the tarsal rake is also a result of abrasion, or whether it is characteristic of the species. Also, the original state of the pubescence on the clypeus and propodeum was probably very different from the current one.
Etymology. Imporcatus comes from the Latin noun porca (ridge between two furrows) and means "put into furrows", referring to the ridges on clypeus and propodeal enclosure of this species.
Syntypes: Australia: Western Australia: Swan River (BMNH). One syntype examined. Diagnosis. Sphex luctuosus differs from all other species in the S. resplendens group in having wings for the most part hyaline and lacking a yellow tinge, but darkened basally. Sphex gracilis also has hyaline wings, but not fuscous basally.
Description. Body black. Appressed pubescence on clypeus and frons silvery, erect setae on clypeus and frons black. Wing membrane darkened basally, forewing with dark costal and marginal cell and a fuscous band at apex. Hindwing membrane hyaline except basally. Clypeus with small glabrous spot medioventrally. Pubescence on top of collar silvery, long lateral setae black. Pubescence on scutum denser laterally. Pubescence on propodeal enclosure silvery-white, thin and sparse enough to leave sculpture completely visible, interspersed with few black setae near posterior end. Female: Body length 24.6-32.4 mm. Wing veins brown to light brown. Forebasitarsal rake with 9-11 long spines. Free clypeal margin with two distinct lobes medially, bulging slightly above; distance between lobes less than 1/8 length of flagellomere II. Distance between hind-ocelli approximately 0.8× their shortest distance to compound eyes. Anterior half of scutum covered with silvery pubescence. Scutellum flat, without impressions. Length of petiole almost equal to flagellomere II. Tomentum sparse on metasomal tergum I, absent on tergum II.
Male: Body length 23.2-26.8 mm. Wing veins dark brown. Free clypeal margin truncate, slightly concave medially. Distance between hind-ocelli 1.25× their shortest distance to compound eyes. Anterior half of scutum covered with black pubescence. Scutellum convex, with shallow medial impression. Length of petiole 1.4× length of flagellomere II. Tomentum moderately dense on metasomal terga I and II. Metasomal terga V and VI with few black bristles. Metasomal sterna II-VI largely glabrous, sternum VII covered with erect black setae, sternum VIII with dense fringe of silvery setae medially. Metasomal sternum VIII entire, its lateral margin straight.

Sphex mimulus R. Turner, 1910
Sphex mimulus R. Turner, 1910: Fig. 24E. Diagnosis. Females of Sphex mimulus are unique among the Australian members of the S. resplendens group in having black legs and the first three segments of the metasoma while the apical three segments are bright ferruginous. Sphex decoratus and some females of Sphex rugifer vary among similar colors, but as a member of the S. argentatus group, the former has a pair of distinct tubercles on the metanotum, whereas Sphex mimulus, as a member of the S. resplendens group, lacks the metanotal tubercles. Sphex rugifer lacks the yellow tinge in the cellular wing area that is present in S. mimulus. Until now, the male of S. mimulus is the only one in the S. resplendens group with a partially orange or yellowish metasoma.
Description. Base of wing membrane darkened, apex slightly fuscous, cellular wing area with pale yellowish tinge. Clypeus with small indentation medioventrally. Appressed pubescence on clypeus and frons silvery, erect setae on clypeus and frons black. Pubescence on mesosoma silvery, on scutum longer and denser laterally. Pubescence on propodeal enclosure sparse and thin, leaving sculpture completely visible. Tomentum on metasomal tergum I moderately dense, on tergum II sparse.
Female: Body length 26.4-32.8 mm. Body black, but apical three metasomal terga and apical 3-4 metasomal sterna orange. Wing veins light to dark brown. Forebasitarsal rake with nine spines. Free clypeal margin with two lobes medially, bulging slightly above; distance between lobes less than 1/8 length of flagellomere II. Clypeus with medial, narrow, more or less glabrous stripe. Distance between hind-ocelli slightly greater than their shortest distance to compound eyes. Scutellum completely flat, without impressions. Petiole slightly shorter than flagellomere II.
Male: Body length 19.6-25.4 mm. Body black, but apical three metasomal terga pale yellowish-orange. Wing veins dark brown. Free clypeal margin truncate. Clypeus medially with mostly glabrous stripe. Distance between hind-ocelli 0.75× their shortest distance to compound eyes. Scutum with faint longitudinal posteromedian impression. Scutellum convex, with medial impression. Length of petiole 1.3× length of flagellomere II. Metasomal terga V and VI with few silvery bristles. Metasomal sterna II and III mostly glabrous, IV-VII with increasingly dense (but still rather sparse) fringes of brown setae laterally, sternum VIII with dense, silvery fringe near apical margin. Metasomal sternum VIII relatively long and tongue-shaped, entire, its lateral margin straight.
Notes on type material. The type of S. mimulus was not examined, because the characters in the original description (metasoma black anteriorly, apical metasomal segments red) are sufficient to unambiguously identifiy this species.  The collecting localities are shown in Fig. 23B. Diagnosis. Sphex resplendens differs from all other examined species in having completely fuscous both fore-and hindwings, a black metasoma that often has a metallic blue lustre, and dark setae on the propodeal enclosure. Sphex gilberti is similar, but has bright yellowish wings.

Sphex resplendens
Description. Body black, legs dark maroon. Metasoma often with blue lustre. Wing membrane uniformly dark, with violet lustre. Wing veins black. Erect setae on clypeus black. Pubescence on collar silvery, with erect black setae. Scutum with silvery pubescence that is denser laterally, anteriorly interspersed with black setae. Propodeal enclosure covered with erect black setae, not concealing sculpture. Length of petiole nearly equal to flagellomere II. Female: Body length 22.1-26.9 mm. Forebasitarsal rake with eight long spines. Free clypeal margin with two incosnpicuous lobes medially, bulging above; distance between lobes less than 1/8 length of flagellomere II. Appressed pubescence on clypeus and frons sparse, thin and silvery. Clypeus medially with large glabrous area. Distance between hind-ocelli 0.9× their shortest distance to compound eyes. Scutellum and metanotum with sparse, erect black setae. Tomentum sparse on metasomal tergum I and II.
Male: Body length 20.5-25.4 mm. Free clypeal margin truncate, concave towards center. Appressed pubescence on clypeus and frons dense and golden. Clypeus with medial glabrous stripe, most of ventral clypeal area glabrous. Distance between hind-ocelli 0.8× their shortest distance to compound eyes. Scutellum and metanotum with sparse, erect silvery setae, laterally with erect black setae. Tomentum moderately dense on metasomal tergum I and II. Metasomal terga V and VI with few black bristles. Metasomal sterna II and III mostly glabrous, sterna IV-VII with brassy pubescence and long black setae at apical margin, densest on sternum VI. Metasomal sternum VIII entire, with few short silvery setae posteriorly, its lateral margin slightly concave there.
Notes on type material. The types of S. resplendens and its synonyms were not examined because the character combination in the original description (black pubescence on propodeum, fuscous wings) is sufficient to unambiguously identifiy this species. Diagnosis. Sphex rhodosoma (of which only the female is known) is unique among the Australian Sphex in combining the features of the S. resplendens group with a mostly orange body including orange legs and a petiole which is slightly longer than flagellomere II. A partially orange mesosoma is also found in Sphex sericeus. In that species, however, the propodeal enclosure is ridged and the metanotum has a pair of distinct tubercles, while S. rhodosoma lacks both these features.
Description. Female: Body length 20.2 mm. Body orange, but the following are black: apical mandibular tooth, frons, vertex, gena, flagellomere II above and flagellomeres III-X entirely, parts of metasomal terga II, III and IV, parts of metasomal sternum II. Wing membrane yellow, with slightly fuscous band near apex. Wing veins brown, orange near base. Forebasitarsal rake with six long spines. Free clypeal margin with two lobes medially, distance between them less than 1/8 length of flagellomere II. Appressed pubescence and erect setae on clypeus and frons silvery-white. Clypeus with medial glabrous stripe. Distance between hind-ocelli equal to their shortest distance to compound eyes. Pubescence on collar and scutum silvery-white, on the latter longer and denser laterally and posteriorly. Scutellum flat, shiny, without impressions. Propodeal enclosure with short, appressed silvery-white pubescence, sculpture almost completely visible. Length of petiole approximately 1.1× length of flagellomere II. Tomentum on metasomal sternum I moderately dense, on sternum II sparse.

Sphex rugifer Kohl, 1890
Sphex rugifer Kohl, 1890: 393, ♀. Syntypes: Australia: no specific locality (ZMB) and Western Australia: Swan River (NHMW). One syntype examined.  Diagnosis. Sphex rugifer differs from other Australian Sphex through a combination of the following characters: uniformly darkened forewing membrane without yellow tinge, hindwing membrane fuscous beyond the cellular area ( Fig. 24A-C), and silvery-white pubescence on the propodeal enclosure. Females can also be identified, in addition to the aforementioned features, in having a red metasoma, though the tone is often very dark. Both sexes of S. resplendens differ in having dark pubescence on the propodeum; and in S. fumipennis, the distal part of the hindwing membrane is hyaline (Fig. 16B). Males of S. fumipennis also have a conspicuous fringe of silvery setae near the apex of metasomal sternum VIII (Fig. 16C), whereas males of S. rugifer lack this pubescence (Fig. 24D).
Description. Pro-and mesosoma black, but the following are light to dark brown: legs excluding coxae and basal half of claws excluding claw teeth. Basal half of mandible reddish. Forewing membrane uniformly fuscous. Hindwing membrane hyaline basally, remainder fuscous. Wing veins dark brown. Appressed pubescence on clypeus and frons silvery, erect setae on clypeus black, on frons silvery. Clypeus with narrow medial glabrous stripe. Pubescence on mesosoma silvery, on scutum denser laterally. Scutellum slightly convex, with shallow medial impression. Pubescence on propodeal enclosure sparse enough to leave sculpture clearly visible. Length of petiole 1.4× length of flagellomere II.
Female: Body length 18.0-20.6 mm. Metasoma ranges from bright red to black with few dark red blurs. Forebasitarsal rake with 9-10 long spines. Free clypeal margin slightly scoop-shaped, with inconspicuous notch medially. Distance between hind-ocelli equal to their shortest distance to compound eyes. Propodeal enclosure with approximately 20 fine transverse ridges. Tomentum moderately dense on metasomal terga I and II.

Species group of Sphex subtruncatus
This group encompasses all species that cannot be assigned to the other two, and is only defined by the lack of specializations found in the other two groups (Hensen 1991). Members are characterized by claw teeth that are obliquely orientated to the claw margin and a mostly plain metanotum without tubercles (see diagnosis of S. argentatus group for details). With 18 Australian species, it is also the largest of the three groups. Nine species are new.

Sphex ahasverus Kohl, 1890
Sphex ahasverus Kohl, 1890: 397, ♀. Holotype or syntypes: Australia: southern Australia: no specific locality (NHMW). Presumed holotype examined. Diagnosis. This species (of which only the female is known) is unique among the members of the S. subtruncatus group in the distance between hind-ocelli being less than 60 % of their shortest distance to the compound eyes. Also, the combination of dense, erect, short black setae on the scutum and the dense golden pubescence on the propodeum makes it easy to identify.
Description. Female: Body length 29.4 mm. Body black. Wing membrane with brown tinge, forewing also with slightly darker band at apex. Wing veins brown. Forebasitarsal rake with eight long spines; it is, however, likely that at least one additional spine was present, but has broken off. Free clypeal margin with two inconspicuous lobes medially, distance between them less than 1/8 length of flagellomere II. Appressed pubescence on clypeus and frons golden, long erect setae black. Clypeus with narrow medial glabrous stripe. Distance between hind-ocelli less than 0.6× their shortest distance to compound eyes. Pubescence on collar silvery. Scutum with short black pubescence which is denser laterally than medially. Scutellum convex, with shallow medial impression. Propodeum with dense, appressed pubescence and longer, more sparse, erect golden setae. Propodeal sculpture completely concealed by pubescence. Length of petiole 1.5× length of flagellomere II. Tomentum moderately dense on metasomal tergum I and II.
Male: Unknown. Geographic distribution. Sphex ahasverus is known solely from the type locality, which is listed only as South Australia. Diagnosis. Females of Sphex argentatissimus are unique among the members of the S. subtruncatus group in combining the following characters: appressed pubescence on clypeus golden, wing membrane without yellow tinge, and pubescence on propodeal enclosure silvery-white. Males differ from those of the other species in possessing, additionally to the aforementioned features, a petiole that is considerably longer than flagellomere II and a conspicuous notch on the apical margin of metasomal sternum VIII. The former feature separates S. argentatissimus from Sphex ermineus, of which the petiole is shorter than flagellomere II, the latter one from Sphex cognatus and Sphex formosellus, in which the apical margin of metasomal sternum VIII is pointed.
Description. Body black. Wing membrane hyaline, with fuscous band at apex. Wing veins dark brown to black. Appressed pubescence on clypeus and frons and erect setae on frons golden. Clypeus almost entirely covered with pubescence. Pubescence on collar and scutum brassy, except laterally and posteriorly on scutum, where it is denser and silvery-white. Scutellum convex. Propodeal enclosure covered with silverywhite pubescence, completely concealing sculpture.
Female: Body length 20.8-21.8 mm. Forebasitarsal rake with nine long spines. Free clypeal margin concave medially, with two lobes there, distance between which is less than 1/8 length of flagellomere II. Clypeus with erect golden setae. Distance between hind-ocelli 1.1× their shortest distance to compound eyes. Scutellum without impressions. Length of petiole 1.6× length of flagellomere II. Tomentum dense on metasomal tergum I and II.
Male: Body length 23.3-24.6 mm. Free clypeal margin truncate. Clypeus with few erect silvery-golden setae. Distance between hind-ocelli equal to their shortest distance to compound eyes. Posterior half of scutum with longitudinal median impression. Scutellum with medial impression near posterior margin. Length of petiole 1.4× length of flagellomere II. Tomentum moderately dense on metasomal tergum I, sparse on tergum II. Metasomal terga V and VI with few bristles. Metasomal sternum VII with small fringe of silvery setae posterolaterally, sterna VI-I each with decreasing amount of setae. Apical margin of metasomal sternum VIII conspicuously notched so that two small lobes are formed, its lateral margin slightly concave posteriorly.
Discussion. The males of this species have very reliable and distinctive features in which they differ from the other Australian Sphex. These features, however, are male sexual characters (free clypeal margin and metasomal sternum VIII) and thus do not help in establishing the sex association. Still, several characters indicate that both males and females belong to a single species.
In the S. subtruncatus group, there are only two species whose clypeal and propodeal pubescence resembles that of S. argentatissimus. One of them, Sphex pretiosus, is easily identifiable in possessing both silvery-white and golden pubescence on the propodeum. The females of the other one, S. cognatus, have golden, silvery-golden or silvery pubescence on the propodeal enclosure and are indeed very similar to those of S. argentatissimus. However, of the many examined females of S. cognatus, none had propodeal pubescence with the conspicuous white tone of silver that is characteristic of the males and females of S. argentatissimus. Wing coloration is a similar case. Females of S. cognatus usually have a partially yellow tinged wing membrane, but sometimes it is almost entirely hyaline. On the other hand, the wings of S. argentatissimus have no hint of yellow at all. Fig. 26B shows that the males and females of this species occur at least in the same overall region.
Etymology. Argentatissimus is the superlative of the Latin adjective argentatus (silvery) and refers to the fact that the silvery color of the propodeal pubescence is much more intense in this one than in the similar species. The collecting localities are shown in Fig. 35B. Diagnosis. Sphex basilicus differs from most other Australian Sphex by the color of its legs, which are orange from the distal half of the femur up to but excluding the claws, while the remaining parts are black or dark brown (sometimes, tarsomeres V are also black). As opposed to other species with orange legs, the metasoma and scutellum of S. basilicus are completely black. The males of this species are also recognizable by the shape of metasomal sternum VIII, which, like Sphex bilobatus and Sphex latilobus, carries two prominent lobes that are visible from above. Unlike these two species, where the lobes are the only visible part of sternum VIII and mostly straight, the lobes of Sphex basilicus are conspicuously curved upward, and a large, undivided portion of sternum VIII is also visible (Fig. 27B).
Description. Body black, but the following are orange: distal part of forefemur, mid-and hindfemora at least below; tibiae, tarsi, and proximal half of claw. Forewing membrane yellow near base, fore-and hindwings with fuscous band at apex. Wing veins brown. Clypeus with narrow medial glabrous stripe. Distance between hindocelli 0.7× their shortest distance to compound eyes. Pubescence on collar and scutum golden, on scutum denser laterally than medially. Scutellum convex, with medial impression. Propodeal enclosure with long, somewhat dense, golden setae; sculpture not completely concealed.
Female: Body length 27.2-31.2 mm. Forebasitarsal rake with eight long spines. Appressed pubescence and erect setae on clypeus and frons golden. Free clypeal margin medially with indistinct emarginations and an indentation directly above, distance between lobes less than 1/8 length of flagellomere II. Length of petiole 1.2× length of flagellomere II. Tomentum golden, dense on metasomal tergum I, moderately dense on tergum II.
Male: Body length 34.4-43.6 mm. Metasomal sternum VIII orange. Appressed pubescence and erect setae on clypeus and frons silvery-white. A single lobe emerging medially and slightly posteriorly from free clypeal margin. Length of petiole 1.6× the length of flagellomere II. Tomentum golden, very dense on metasomal tergum I where it is also interspersed with dense, long, erect golden setae, moderately dense on tergum II. Metasomal terga V and VI with long, golden setae facing posteriorly, especially at apical margin. Metasomal sterna mostly glabrous, several long golden setae laterally on sterna V-VII. Metasomal sternum VIII with two lobes that are curved upward and diagonally truncate posteriorly.
Notes on type material. The type of S. basilicus was not examined because the character combination in the original description (black body, golden pubescence on clypeus and propodeum, partially ferruginous legs) is sufficient to unambiguously identifiy this species.  1♀, 14.11.1944 (AMS). AUSTRALIA: ACT: Cotter Road, Weston Creek, 1♀, 10.01.1931, G. Jefferies (ANIC); NSW: 6 km N of Bilpin, Blue Mountains, 1♂, 27.11.1979, N. W. Rodd (AMS); 6 km NE of Bilpin, Blue Mountains, 1♂, 14.11.1980, N. W. Rodd (AMS), 1♀, 22.01.1988 The collecting localities are shown in Fig. 34B. Diagnosis. Females of Sphex bilobatus differ from the other Australian Sphex by the following character combination: metanotum without tubercles, metasoma black, wing veins light to dark brown, appressed pubescence and erect setae on clypeus silvery-white, and scutellum convex medially. Males of S. bilobatus are also characterized by their metasomal sternum VIII, which consists of two large separate lobes (Fig. 28B). This character is only shared with males of two other Australian species. One of them, Sphex basilicus, has a single lobe emerging from below the center of the free clypeal margin, is much larger in size and has orange pubescence on the propodeal enclosure, whereas S. bilobatus does not have lobes on the free clypeal margin, and its propodeal pubescence is silvery. In the other one, Sphex latilobus, the free clypeal margin is bright orange, while that of S. bilobatus is black.

Sphex bilobatus Kohl, 1890
Description. Body length 19.0-22.6 mm. Body black. Wing membrane hyaline, forewing with slightly fuscous band at apex. Wing veins light to dark brown. Free clypeal margin medially with broad, insignificant lobe that emerges slightly posteriorly of clypeal surface. Appressed pubescence and erect setae on clypeus and frons silverywhite. Clypeus with medial glabrous stripe. Pubescence on collar and scutum silverywhite, on scutum not significantly denser laterally than medially. Scutellum convex, with medial impression. Propodeal enclosure with sparse, silvery-white pubescence, sculpture well visible. Length of petiole 1.4× length of flagellomere II. Tomentum rather sparse on metasomal tergum I, moderately dense on tergum II.
Female: Hindwing entirely hyaline. Forebasitarsal rake with 11 long spines. Free clypeal margin slightly scoop-shaped. Distance between hind-ocelli slightly smaller than their shortest distance to compound eyes.
Male: Hindwing with slight fuscous band at apex. Distance between hind-ocelli equal to their shortest distance to compound eyes. Metasomal terga V and VI with few bristles. Metasomal sterna II-VII with few, erect silvery setae posterolaterally. Visible part of metasomal sternum VIII forming two separated lobes. Notes on type material. The types of S. canescens F. Smith, 1856 (the original, invalid name of the species) were not examined, but we did study the types of S. bilobatus Kohl, 1890, which was synonymized with S. canescens by R. Turner (1910). The collecting locality is shown in Fig. 35B. Diagnosis. Sphex brevipetiolus (of which only the female is known) is one of the few species in the S. subtruncatus group with a petiole shorter than flagellomere II. It differs from females of Sphex ermineus and Sphex corporosus, which are similar, in having bright orange veins near the wing base and a markedly convex scutellum with a distinctly developed impression medially. Sphex ermineus has black wing veins, and the scutellum of S. corporosus is flatter and often lacks an impression.

Sphex brevipetiolus
Description. Female: Body length 31.6 mm. Body black. Wing membrane hyaline, with fuscous spot beyond marginal cell. Wing veins orange, darker near apex. Forebasitarsal rake with nine long spines. Free clypeal margin with two small lobes medially, distance between them less than 1/8 length of flagellomere II. Appressed pubescence and erect setae on clypeus and frons silvery-white. Clypeus with medial glabrous stripe. Distance between hind-ocelli 0.8× their shortest distance to compound eyes. Pubescence on collar, scutum, metanotum and propodeum silverywhite, on scutum denser laterally. Scutellum convex, with medial impression. Pubescence on propodeal enclosure not concealing sculpture. Length of petiole 0.8× length of flagellomere II. Tomentum moderately dense on metasomal tergum I, slightly denser on tergum II.
Male: Unknown. Discussion. In the S. subtruncatus group, there are eight species of which females are yet unknown or where matching of males and females was first proposed in this study. Sphex brevipetiolus can theoretically be the female of one of them. Of these, only three have wing veins that are not uniformly dark. One of them (Sphex flammeus) has a bright orange metasoma and largely orange legs. The second one (Sphex pretiosus) has a sharp transition between golden and silvery pubescence on the propodeum and, like the former, a petiole that is considerably longer than flagellomere II. Finally, the reasons for ruling out S. corporosus are given in the respective discussion.
Etymology. Brevipetiolus is a composite of the Latin adjective brevis (short) and the noun petiolus (stem), referring to the short petiole of this species. The collecting locality is shown in Fig. 42D. Diagnosis. The presence of a few dark erect setae on the clypeus combined with partially orange legs (mainly parts of the anterior surface of the foreleg, as seen in Fig. 30B, and the inner hindtibial spur including pecten) make Sphex caelebs unique among the male Australian Sphex (the female of this species is unknown). The habitus and mesosomal sculpture resemble some Sphex modestus, which possesses an only inconspicuously raised metanotum and dense white or yellowish tufts of setae on the metasomal sterna that are absent in S. caelebs.
Description. Female: Unknown. Male: Body length 18.1 mm. Body black, but the following are orange-brownish: basal half of mandible, anterior surface of foreleg from distal half of femur up to tarsomere IV, distal half of anterior surface of midfemora, inner hindtibial spur including pecten, basal half of claw. Wing membrane hyaline, forewing with slightly fuscous band at apex. Wing veins dark brown. Free clypeal margin simple, concave medially. Appressed pubescence on clypeus and frons silvery-white, a few dark erect setae on clypeus, remaining erect setae on clypeus as well as those on frons uniformly silverywhite. Clypeus medioventrally with narrow glabrous stripe. Distance between hindocelli nearly equal to their shortest distance to compound eyes. Pubescence on mesosoma silvery-white, on scutum slightly denser laterally. Scutellum convex, with shallow medial impression. Pubescence on propodeal enclosure sparse, leaving sculpture fully visible. Length of petiole 1.6× length of flagellomere II. Tomentum moderately dense on metasomal tergum I and II. Metasomal terga V and VI sparsely covered with erect silvery setae. Metasomal sterna II-VI mostly glabrous, apical half of sternum VII and all sternum VIII covered with silvery pubescence. Metasomal sternum VIII entire, its lateral margin straight.
Discussion. It must also be assessed if Sphex caelebs is the undescribed male of an already known species. In the Sphex subtruncatus group, there are seven species of which males are yet unknown or where matching of males and females was first proposed in this study. In none of these, however, is the leg coloration comparable to S. caelebs, and additional characters indicate its status as a separate species. For example, only two of the seven species also have dark erect setae on the clypeus. These two, however, are much larger than S. caelebs; one of them, Sphex ahasverus, has darkened wings and golden pubescence on the propodeum and the other one, Sphex corporosus, has an unusually short petiole, the characters that are lacking in S. caelebs.
Etymology. Caelebs is a Latin noun meaning "unmarried man", referring to the fact that the species is currently known only from a single male.
Male: Forewing membrane hyaline or with slight yellow tinge, hindwing membrane hyaline. Wing veins brown. Lobes on free clypeal margin emerge slightly posteriorly of clypeal surface. Scutellum with shallow medial impression. Metasomal tergum V with few, tergum VI with considerable number of silvery-golden bristles. Metasomal sterna IV-VIII each with increasingly dense brown pubescence apically. Apical margin of metasomal sternum VIII arcuate, its lateral margin concave.
Diagnosis. Sphex corporosus can be distinguished from most other members of the S. subtruncatus group through a combination of the following characters: petiole shorter than flagellomere II and pubescence on propodeal enclosure not concealing sculpture. Presence of these traits is sufficient to identify males, while females of S. corporosus resemble those of Sphex brevipetiolus. The former, however, has a flat scutellum (Fig. 32B) as well as dark erect setae on the clypeus, whereas in the latter the scutellum is convex and only silvery-white erect setae are present on the clypeus.
Description. Body black, mandible medially with ferruginous stripe, legs and metasoma dark maroon to black. Wing membrane hyaline, forewing with fuscous spot beyond marginal cell. Wing veins dark orange to dark brown. Appressed pubescence on clypeus and frons as well as erect setae on frons silvery. Pubescence on mesosoma silvery-white. Propodeal enclosure covered with long, erect, silvery-white pubescence, not concealing sculpture. Pubescence denser on posterior end of propodeum.
Female: Body length 27.5-31.8 mm. Apical margin of forewing fuscous beyond submarginal cell III, medial cell II and cubital cell II. Forebasitarsal rake with 10-11 long spines. Free clypeal margin slightly scoop-shaped, clypeus elevated medially above margin. Erect setae on clypeus black. Most of central clypeal area glabrous. Distance between hind-ocelli 0.9× their shortest distance to compound eyes. Scutum glabrous except for area between admedian lines and lateral and posterior margins. Scutellum flat, sometimes with shallow medial impression. Length of petiole 0.7× length of flagellomere II. Tomentum moderately dense medially on metasomal tergum I, metasomal tergum II glabrous. Metasomal terga V and VI with few bristles.
Male: Body length 20.3-27.4 mm. Apical margin of forewing nearly hayaline beyond submarginal cell III, medial cell II and cubital cell II. Free clypeal margin truncate, slightly concave towards center. Erect setae on clypeus silvery. Clypeus with narrow medial glabrous stripe which broadens towards free clypeal margin. Distance between hind-ocelli 1.3× their shortest distance to compound eyes. Pubescence on scutum much denser laterally. Scutellum convex, with medial impression. Length of petiole 0.8× length of flagellomere II. Metasomal tergum I and anterior half of metasomal tergum II very densely covered with silvery-white tomentum. Metasomal sternum VII with small fringe of dark bristles posterolaterally. Metasomal sternum VIII notched apically, its lateral margin concave.
Variation. In most of the examined specimens, the metanotum is moderately raised, and in a few with an inconspicuous median impression. A raised metanotum with an impression is usually distinctive for species of the S. argentatus group, but since the raising of the metanotum and the depth of the impression in the most extreme known cases of this species are only comparable to the least extreme cases of examined specimens of the S. argentatus group, S. corporosus is tentatively placed in the S. subtruncatus group.
Discussion. Save for two other species besides S. corporosus, all members of the S. subtruncatus group have a petiole longer than flagellomere II. One of them, Sphex ermineus, is set apart by having exceptionally long and dense pubescence on the propodeal dorsum. Of the other one, S. brevipetiolus, only a single female is known. This specimen differs in a few features from the specimens that have been designated the females of S. corporosus, and partially surpasses them in resemblance to the males of S. corporosus. Arguments in favor of pairing males and females of S. corporosus are addressed in the subsequent paragraph.
The following attributes are shared by S. brevipetiolus and males of S. corporosus, but not between males and females of the latter: erect setae on clypeus uniformly silvery-white, and scutellum convex and medially impressed. However, the scutellar structure is usually not constant among sexes in the Australian Sphex. On the other hand, S. brevipetiolus has several features that differentiate it from both males and females of S. corporosus: considerably shorter tomentum on metasomal tergum I, brassy setae on metasomal sterna, and wing veins that are bright orange in the basal half of the wing. For these reasons, males and females of S. corporosus are considered to be one species, and S. brevipetiolus is treated as a separate one.
Lastly, the geographic range of both sexes is also indicative of the status as a single species, particularly since the number of examined individuals was rather large. Males and females were often found in close proximity to each other, or even in the same areas (Fig. 32C).
Etymology. Corporosus is a Latin adjective, meaning "corpulent". A few members of this species from the ANIC were already labeled with this name, although it is unclear by whom. There are no related publications, but the species will be named S. corporosus to minimize the risk of confusion in case there are more specimens already so labeled. It undoubtedly refers to the large size of the species.  Fig. 42D. Diagnosis. Sphex ermineus differs from all other Australian Sphex in the combination of a petiole distinctly shorter than flagellomere II, and the dense, long, silverywhite pubescence on the propodeal enclosure that conceals the sculpture. Sphex corporosus has a similar appearance, but its propodeal pubescence is less dense, leaving parts of the sculpture still visible.

Sphex ermineus
Description. Body length 28.8-30.8 mm. Body black. Wing membrane hyaline, forewing with dark fuscous spot beyond marginal cell. Wing veins black. Distance between hind-ocelli approximately 1.2× their shortest distance to compound eyes. Pubescence on collar and scutum silvery-white, denser laterally and posteriorly. Propodeal enclosure densely covered with silvery-white pubescence, sculpture completely concealed. Length of petiole approximately 0.9× length of flagellomere II. Tomentum on metasomal tergum II mostly absent.
Male: Forewing almost hyaline at apex except for fuscous spot beyond marginal cell. Free clypeal margin concave medially. Appressed pubescence and erect setae on clypeus and frons golden. Clypeus with narrow medial glabrous stripe. Central area of scutum and scutellum pubescent. Tomentum on metasomal tergum I dense. Metasomal sternum I medially densely covered with long, silvery setae. Sterna II-VIII with increasingly dense fringes of silvery setae laterally, sterna VII and VIII completely covered. Metasomal sternum VIII anteriorly with large hole, conspicuously notched apically, its lateral margin concave (Fig. 33B).
Notes on type material. The type of S. ermineus was not examined, because the chara cter combination in the original description (dense silvery-white propodeal pubescence, flat scutellum, flat metanotum) is sufficient to unambiguously identify this species. Diagnosis. Females of Sphex flammeus (the male is unknown) differ from other Australian Sphex by the following combination of features: appressed pubescence on clypeus silvery-white, scape, legs and metasoma largely orange, and wing membrane without a yellow tinge. Sphex decoratus, S. sericeus, S. darwiniensis and S. rhodosoma are also largely orange, but they are members of different species groups. Sphex staudingeri differs in having golden pubescence on clypeus and scutum instead of silvery-white one and moderately fuscous wings instead of hyaline ones, while also being considerably larger.
Description. Female: Body length 19.6-20.2 mm. Body orange, but the following are black: mandible and claws distally, head excluding clypeus, antenna from the pedicel onward, scutum, sometimes scutellum and metanotum. Wing membrane hyaline, forewing with faint fuscous band at apex. Wing veins range from orange to dark brown. Forebasitarsal rake with 11 long spines. Free clypeal margin straight. Appressed pubescence and erect setae on clypeus and frons silvery-white. Clypeus with medial glabrous stripe. Distance between hind-ocelli 0.9× their shortest distance to compound eyes. Pubescence on mesosoma partly golden, partly silvery, on scutum denser laterally and posteriorly. Scutellum convex, with distinct medial impression. Pubescence on propodeal enclosure short; mostly concealing sculpture. Length of petiole approximately 1.2× length of flagellomere II. Tomentum moderately dense on metasomal tergum I, sparse on tergum II.
Male: Unknown. Variation. One of the three examined specimens has a median impression on the metanotum; this trait is also distinctive for species of the S. argentatus group. However, it is there accompanied by a conspicuous raising of the metanotum, which S. flammeus lacks. Therefore, this species is tentatively placed in the S. subtruncatus group.
Discussion. The character combination of the available females makes it clear that this species has not yet been described. Based on species group membership, there are eight species of which females are yet unknown or where matching of males and females was first proposed in this study. Sphex flammeus can theoretically be the female of one of them. However, only one of them, Sphex semifossulatus, is also colored bright orange. Still, both differ in the color of scapes and propodeum, as well as in the orientation of the mesosomal pubescence, which is denser and more appressed in S. flammeus.
Etymology. Flammeus is a Latin adjective, meaning "flame-colored". It refers to the color of this species.  -22.12.1958, A. Snell (AMS). INDONESIA: East Nusa Tenggara: Timor, 1♂ (ZMB). Diagnosis. Sphex formosellus differs from other members of the S. subtruncatus group in combining the following characters: the clypeus is entirely covered with dense pubescence, the pubescence on the propodeal enclosure is sparse enough to leave the sculpture visible, and the legs are black. In contrast, the legs of Sphex staudingeri and at least the foretibia of Sphex caelebs are bright orange.
Female: Membrane of cellular wing area yellow, remainder hyaline. Wing veins yellowish-orange, darker near apex. Forebasitarsal rake with nine long spines. Free clypeal margin with two lobes medially, distance between them less than 1/8 length of flagellomere II. Distance between hind-ocelli equal to their shortest distance to compound eyes. Pubescence on collar, scutum and propodeal enclosure silvery-golden. Scutellum without impressions. Tomentum dense on metasomal terga I and II.
Male: Wing membrane hyaline. Wing veins light brown. Free clypeal margin truncate. Distance between hind-ocelli 1.3× their shortest distance to compound eyes. Pubescence on collar, scutum and propodeal enclosure silvery-white. Scutellum with medial impression. Tomentum very dense on metasomal tergum I and II. Metasomal terga V and VI covered with silvery-golden bristles. Metasomal sterna VI-VIII with fringes of silvery setae laterally, densest on sternum VII. Metasomal sternum VIII entire, its lateral margin concave.
Notes on type material. The types of S. formosellus were not examined, because the character combination for females in the original description (black body, two lobes on free clypeal margin, wing membrane hyaline with yellow tinge, clypeus and propodeal enclosure with brassy pubescence, pubescence less dense than in S. cognatus) is sufficient to unambiguously identify this species. Diagnosis. This species differs from other members of the S. subtruncatus group mainly in the color of the wing membrane, which is markedly fuscous near the base and around the subcosta as well as below the submedial cell. This seems to be the only character that differentiates the species from Sphex jucundus, which has the wing mem- brane hyaline in this area. The absence of tubercles on the metanotum and the lack of erect dark setae on the clypeus distinguish Sphex fortunatus from Sphex finschii in the S. argentatus group, which has similar wing coloration.
Description. ♀. Unknown. Male: Body length 20.6 mm. Body black, mandible dark ferruginous in center, femora maroon. Wing membrane light brown, markedly fuscous around subcosta and below submedial cell. Wing veins dark brown to black, cellular area around veins on forewing fuscous. Free clypeal margin slightly concave towards center, with minute lobe there. Appressed pubescence and erect setae on clypeus and frons silvery. Clypeus glabrous ventrally and with narrow glabrous stripe medially. Distance between hind-ocelli slightly smaller than their shortest distance to compound eyes. Pubescence on mesosoma silvery-white, on scutum longer and denser laterally and posteriorly. Scutellum convex, with shallow medial impression. Pubescence on propodeal enclosure sparse, sculpture completely visible. Length of petiole 1.5× length of flagellomere II. Tomentum moderately dense on metasomal tergum I, sparse on tergum II. Metasomal terga V and VI with few bristles. Metasomal sterna II-VI mostly glabrous, VII and VIII with moderately sparse silvery pubescence. Metasomal sternum VIII entire, its lateral margin concave.
Geographic distribution. Only one specimen of S. fortunatus could be studied, and no specific geographic information is available. Its origin is given as "North Queensland".
Discussion. There are seven species in the S. subtruncatus group of which males are yet unknown or where matching of males and females was first proposed in this study. Sphex fortunatus can theoretically be the male of one of them. Two of them have a petiole that is markedly shorter than flagellomere II, while two others differ in having pubescence on the propodeal enclosure that is dense enough to conceal the sculpture. One of the three remaining species (Sphex flammeus) is mostly orange in its body color, and another one (Sphex pretiosus) has a mix of golden and silvery pubescence on the propodeum and wing veins that are bright orange in the basal wing half. The last species, S. jucundus, differs, as already mentioned, in having wings that are completely hyaline except near the apex.
Etymology. Fortunatus is a Latin adjective, meaning "happy" or "lucky". The name was chosen in reference to S. jucundus, which is very similar in appearance. Two of those are distinguished in having golden pubescence on the propodeal enclosure, and the petiole of the other two is considerably shorter than flagellomere II.

Sphex jucundus
One character was found in which males and females of S. jucundus differ from each other and which is usually not a sexually dimorphic feature among Australian Sphex, the density of the pubescence on the propodeal enclosure. However, this argument alone would not be sufficient to demonstrate that they belong to different species. The identical coloration of the wings in males and females as well as the conspicuously dense tomentum both have on their metasomal tergum I are only a few of their shared features. Finally, a great number of males and females come from the same or from nearby localities, which is another indication that both form one species (Fig. 26).
Etymology. Jucundus is a Latin adjective, meaning "pleasant" or "merry". The name was apparently chosen by J. van der Vecht when he so labeled individuals of this species in the 1970s, but without describing it. The name was adopted to credit J. van der Vecht. The collecting localities are shown in Fig. 40C. Diagnosis. The males of this species (females are unknown) are easily identifiable by the bright orange coloration along the free clypeal margin, combined with the visible part of the metasomal sternum VIII modified into two completely separate lobes (Fig. 38B). Sphex bilobatus and Sphex basilicus possess similar structures, but the free clypeal margin is black in both species, and the latter also has golden pubescence on the propodeal enclosure, whereas the pubescens is silvery-white in S. latilobus.

Sphex latilobus
Description. Female: Unknown. Male: Body length 18.8-24.5 mm. Body black, but the following are orange: mandible from base up to base of inner tooth, clypeus along free margin, fore-and at least partially midfemur, posterior half of tegula. Wing membrane almost completely hyaline, wing veins dark brown. Free clypeal margin straight or minimally convex. Appressed pubescence and erect setae on clypeus and frons silvery-white. Clypeus with medial glabrous stripe. Distance between hind-ocelli equal to or slightly smaller than their shortest distance to compound eyes. Pubescence on mesosoma silvery-white, on scutum denser laterally and posteriorly. Scutellum convex, with distinct medial impression. Pubescence on propodeal enclosure short, not completely concealing sculpture. Length of petiole 1.3× length of flagellomere II. Tomentum moderately dense on metasomal tergum I, sparse on tergum II. Metasomal terga V and VI with only few bristles. Metasomal sterna II-VIII mostly glabrous. Visible part of metasomal sternum VIII forming two large, completely separated lobes (similar to Sphex bilobatus, shown in Fig. 28B; but lobes of Sphex latilobus are wider). Variation. Of the three examined specimens, the legs of one are almost entirely black, whereas the fore-and parts of the midfemur of the other two are orange.
Discussion. Sphex latilobus is clearly an undescribed species. It also seems unlikely that it can be associated with one of the species based solely on females. Within the S. subtruncatus group, there are seven species of which males are unknown or where matching of males and females was first proposed in this study. Since most diagnostic characters of this species are suspected to be sexually dimorphic, the number of potential candidates was first narrowed down by eliminating all species where matching of males and females is well-founded (Sphex jucundus, Sphex corporosus and Sphex pretiosus), which leaves four species. One of them (Sphex brevipetiolus) has partially orange wing veins and a petiole that barely reaches the length of flagellomere II; another one (Sphex ahasverus) has dark setae on the clypeus, fuscous wings and golden propodeal pubescence. Of the remaining two, one (Sphex argentatissimus) has a clypeus with golden pubescence; the body of the other one (Sphex flammeus) is mostly bright orange. Thus, S. latilobus is unlikely to match any of the currently recognized species.
Etymology. Latilobus is a composite of the Latin words latus (wide) and lobus (elongated projection), referring to the lobes on male sternum VIII which are similar to those of S. bilobatus but wider. Diagnosis. This species is unique among the Australian Sphex in having a more or less sharp transition in the color of the pubescence on the clypeus and the propodeal dorsum. On the ventral part of the clypeus and the outer and posterior margin of the propodeal enclosure, the pubescence is silvery-white; while it is golden on the dorsal part of the clypeus and silvery-golden to golden on the propodeal enclosure. Moreover, the metasomal sternum VIII in males is spoon-shaped and has a gentle notch at the apical margin (Fig. 39B).
Description. Forewing membrane posterobasally with slight yellow tinge, with fuscous band at apex. Wing veins bright orange, brown near apex. Appressed pubescence on ventral part of clypeus silvery-white, on dorsal part and frons silvery-golden. Erect setae matching respective color of appressed pubescence on clypeus, silvery-white on frons. Clypeus almost entirely covered with pubescence. Distance between hindocelli 1.25× their shortest distance to compound eyes. Pubescence on scutum denser laterally and posteriorly. Scutellum convex, with medial impression. Pubescence on propodeal enclosure not completely concealing sculpture. Propodeal pubescence outside enclosure and on petiole silvery-white. Length of petiole nearly twice length of flagellomere II. Tomentum moderately dense on metasomal tergum I.
Female: Body length 17.7-18.8 mm. Body black except mandible reddish basally. Free clypeal margin with two lobes medially and with another less-pronounced lobe on each side of the aforementioned; distance between each two lobes less than 1/8 length of flagellomere II. Forebasitarsal rake with 12 long spines. Pubescence on collar, scutum and propodeal enclosure silvery-white to silvery-golden. Tomentum moderately dense on metasomal tergum II.
Male: Body length 18.4-18.7 mm. Body black. Free clypeal margin slightly concave, convex near center. Pubescence on collar and scutum silvery-golden to golden, on propodeal enclosure golden. Tomentum very dense on metasomal tergum II. Metasomal terga V and VI with few bristles. Metasomal sterna III-VIII with silvery pubescence. Metasomal sternum VIII mostly covered by VII; with long, narrow, spoonshaped extension that has a small notch at apical margin.
Variation. In a few of the examined specimens, the metanotum is moderately raised, and in one of these, there is a slight median impression on it. A raised metanotum with an impression is usually distinctive for species of the S. argentatus group, but since the raising of the metanotum and the depth of the impression in the most extreme known cases of this species are only comparable to the least extreme cases of examined specimens of the S. argentatus group, S. pretiosus is tentatively placed in the S. subtruncatus group.
Discussion. Males and females of S. pretiosus have nearly identical features that are also unique among the Australian species, such as the transition between golden and silvery-white pubescence on the clypeus and the propodeal dorsum. Also, the conspicuously modified sternum VIII of the male substantiates a full species status. Fig. 39C shows that the proposed males and females at least occur in the same region.
Etymology. Pretiosus is a Latin adjective, meaning "valuable" or "costly". It metaphorically refers to the combination of golden and silvery pubescence on the mesosoma of this species.  Material examined. Holotype (presumed). ♂, AUSTRALIA: WA: Champion Bay, now Geraldton (BMNH). Diagnosis. Males of Sphex semifossulatus (females are unknown) are unique among the Australian Sphex in having two lobes on the free clypeal margin that are conspicuously far apart (Fig. 40B). The distance between them is equal to almost half the length of flagellomere II. Of the other examined species, only the males of Sphex cognatus also have two lobes on the clypeus, but those are merely separated by a small notch.

Sphex semifossulatus van der Vecht, 1973
Description. Female: Unknown. Male: Body length 23.2 mm. Body black, but the following are orange: base of mandible, center of free clypeal margin, tegula, metasoma, legs excluding coxae and distal part of hindtibia as well as claw teeth and distal half of claw. Forewing membrane with yellow tinge near base and slightly fuscous band at apex, hindwing membrane hyaline. Wing veins orange, darker near apex. Free clypeal margin with two lobes, distance between them more than half length of flagellomere II. Appressed pubescence and erect setae on clypeus and frons silvery-white. Clypeus with narrow medial glabrous stripe. Distance between hind-ocelli 1.2× their shortest distance to compound eyes. Pubescence on collar and scutum silvery-golden, on the latter denser laterally and posteriorly. Scutellum convex, with distinct medial impression. Propodeal enclosure with silvery-golden pubescence, leaving sculpture mostly visible. Length of petiole 1.25× length of flagellomere II. Tomentum dense on metasomal tergum I and II. Metasomal terga V and VI covered with silvery bristles. Metasomal sterna II-VII each with increasing amount of erect silvery setae laterally. Metasomal sternum VIII with few erect silvery setae, notched apically, its lateral margin straight, convex posteriorly.
Holotype or syntypes: ♂, New Guinea: no specific locality (Genova). Presumed holotype examined. Diagnosis. Sphex staudingeri is unique among the Australian Sphex in combining orange scapes, golden propodeal pubescence and the absence of tubercles on the metanotum. Sphex basilicus differs in having black scapes and a black metasoma, whereas the metasoma of S. staudingeri is orange, although sometimes in a very dark tone.
Female: Body length 29.0 mm. Body black, but the following are orange: mandible proximally, mouthparts, clypeus, scape, pedicel, scutellum, metanotum, metasoma, legs excluding coxa and proximal part of trochanter as well as claw teeth and distal half of claw. Wing membrane uniformly light brown. Forebasitarsal rake with nine long spines. Free clypeal margin with indistinct emarginations. Clypeus medioventrally with glabrous spot. Distance between hind-ocelli 0.8× their shortest distance to compound eyes. Tomentum moderately dense on metasomal tergum II.
Male: Body length 27.2-28.2 mm. Body black, but the following are orange: mandible proximally, mouthparts, metasomal segment I at least partially, legs excluding coxa and trochanter as well as claw teeth and distal half of claw. Wing membrane with yellow tinge in cellular area and with slightly fuscous border at apex. Free clypeal margin truncate, concave towards center. Clypeus with narrow medial glabrous stripe. Distance between hind-ocelli slightly smaller than their shortest distance to compound eyes. Tomentum dense on metasomal tergum II. Metasomal terga V and VI with few golden bristles. Metasomal sterna II-IV mostly glabrous, V-VIII with few reddishgolden bristles laterally. Metasomal sternum VIII entire, slightly arched towards ventral side, truncate at apical margin, its lateral margin straight. black. Clypeus medioventrally with inconspicuous indentation. Appressed pubescence and erect setae on clypeus and frons golden. Pubescence on mesosoma golden, on scutum longer and denser laterally. Posterior half of scutum with longitudinal median impression. Scutellum convex, with medial impression. Pubescence on propodeal enclosure dense, completely concealing sculpture. Tomentum very dense on metasomal sternum I, dense on sternum II.
Female: Body length 26.3-30.0 mm. Forebasitarsal rake with ten long spines. Free clypeal margin with two small lobes medially, distance between them less than 1/8 length of flagellomere II. Clypeus medioventrally with triangular glabrous area. Distance between hind-ocelli almost equal to their shortest distance to compound eyes. Length of petiole 1.4× length of flagellomere II.
Male: Body length 23.0-26.6 mm. Free clypeal margin broadly emarginated, with a broad triangular median lobe. Clypeus glabrous directly above margin. Distance between hind-ocelli 1.1× their shortest distance to compound eyes. Length of petiole 1.5× length of flagellomere II. Metasomal terga V and VI with few golden bristles. Metasomal sterna II-VIII with increasing number of erect golden setae laterally. Metasomal sternum VIII with two markedly raised longitudinal carinae forming a channel- like structure, and with distinct notch at apical margin. Lateral margin of metasomal sternum VIII straight.
Notes on type material. The types of S. vestitus and its synonyms were not examined, because the character combination in the original description (black body, uniformly golden pubescence on clypeus and mesosoma, hyaline wing membrane) is sufficient to unambiguously identify this species.

Discussion
In the following paragraphs, a few of the problematic species whose geographic distribution is partially inconclusive are addressed, and relevant characters are discussed.
As mentioned earlier, no specimens of S. finschii from Australia were found among the studied material, but the notes on geographic distribution by Hensen (1991) imply that he has seen some.
For Sphex staudingeri, the situation is a bit more ambiguous. No Australian specimens could be examined, but Berland (1928) lists a specimen of S. staudingeri from Port Jackson (now part of Sydney). The species has a rather conspicuous appearance, so misidentification is quite unlikely. On the other hand, no specimens of S. staudingeri from Australia other than that listed by Berland are known, which means that this locality record, also given its age, is probably incorrect.
Almost nothing is known about S. australis (Gmelin, 1790). The type was destroyed in the past (Pulawski 2014), and the original description is short and vague. This species has not been mentioned in any other publication besides the initial description, and it seems likely that it is a synonym of another species, possibly even in a different genus (Pulawski 2014). Thus, Sphex australis was ignored in this work.
The geographic distribution of Sphex habenus (Say, 1832) is also not entirely clear. Kohl (1890) described S. princeps, which was synonymized with S. habenus (Fernald, 1931). Sphex habenus is found in the southern part of the USA and in Mexico, and localities outside of America are not known. However, Kohl stated the locality of the type specimen of S. princeps as "country unknown, probably Australia". Based on the available information, his assumption is probably incorrect, since S. habenus was neither found by Hensen (1991) nor among the specimens that were examined in this study.
Based on Pulawski (2014), there are 118 described species of Sphex worldwide, and 37 of these can be found in the overall region of Malesia, the Bismarck Archipelago (BA), the Solomon Islands (SI), and Australia. Their currently known distribution is as follows: § 23 species found in Australia § 16 of them endemic § 21 species found in Malesia/BA/SI § 14 of them not yet detected in Australia § 7 species with known localities in Australia as well as Malesia/BA/SI Taking into consideration the species that were newly discovered in the course of this study, the number of Australian species rises from 23 to 34. Only one of the newly described species, Sphex corporosus, is also known from outside of Australia, and this is supported by merely one specimen. The reason almost no new Malesian species were discovered here is probably the fairly small amount of material that was collected from the area; the region was also covered by Hensen (1991).
Using the gathered locality data of each species of Sphex, diversity and geographic distribution among countries and federal states was assessed at a more general level. Fig. 43A depicts this for Australia. As shown, Queensland is the state with the largest number of different Sphex species (19), while Western Australia is the one with the most endemic ones (6). New South Wales, while on par with Western Australia in its total number of species, completely lacks endemics. A possible explanation for this can be found in the Australian climate zones (Fig. 43B). Assuming that the deserts function more or less as a barrier against dispersal and hybridization, Sphex species from Western Australia (all of which are only known from the western half of the state) are much more geographically separated than those of the other states. On the other hand, New South Wales contains only a rather small desert area and shares all of its climate zones with at least one of the neighboring states, so species dispersal among these states is less constrained.
Even though it might be tempting, we do not feel qualified to estimate the number of still undiscovered Sphex species. There are many papers which attempt to assess global or local species richness based on the examination of a single taxon, and the resulting numbers are vastly different and likely unreliable (Erwin 1982;Hodkinson and Casson 1991;Colwell and Coddington 1994). Even when ignoring this fact, the Australian continent as a whole is much too heterogeneous to be used as a reference site, and on a smaller as well as on a greater scale, the sample size in this study is not large enough for a reasonable estimate.
Not all characters that are known to be useful for species delimitation in Sphex were utilized in this study. Since the main aim was to generate a key that is easy to use, does not involve inflicting damage on the individual, and also works on dried and older specimens, the use of genetic characters or that of features which require dissection of the specimen to be studied was ruled out from the start. Also, some morphological characters were not included for different reasons. For example, some traits seem useful for species discrimination at first glance, but have a high intraspecific variability. Such are the presence of an impression on the collar, the presence of a pale spot on the underside of the scape, and the color of compound eyes and ocelli. In these instances, it was found that the variation was independent of the specimens' physical condition and preservation status.
A few characters that were mentioned by authors in the past have been omitted in this study, since they were not found to be of particular use. For instance, Bohart and Menke (1976) stated that S. darwiniensis and S. rugifer are atypical in the narrow ventral, terminal, blade-like setae of the last hindtarsomere. However, examination of the two species did not provide any significant differences between these and their congeners. Characters whose thorough inspection across all species was deferred for time reasons, but which will probably be valuable for subsequent studies, include (among others): length/width relation of the clypeus, placoid pattern on the male antenna, and structure of the mesosomal sculpture. The latter was occasionally used to reinforce proposed matching of male and female specimens, but actual classification and delimitation of the different patterns as well as recognizing variation is undoubtedly a challenging task.
Finally, we are aware that description of a new species based solely on a single specimen can be regarded as problematic. It has been done in this paper for S. caelebs, S. brevipetiolus, and S. fortunatus. Still, at least in the former two, more than one character differentiates them from all other Australian Sphex, which reduces the chances that these are merely intraspecific variations of existing species. On the other hand, S. fortunatus differs indeed only in the wing color from S. jucundus, so conspecificity of these two seems possible. Nonetheless, the presence or absence of darkening on the base and center of the wing is apparently a rather invariable character in Sphex.
Concerning the wings of the examined material, the only features where significant intraspecific differences were observed are the color of the veins, the presence of yellow tinge, slight variations in the extent of wing area coloration, and the intensity of the fuscous band near the apex. Based on this, it was deemed reasonable to grant S. fortunatus the status of a separate species.