Holotype. one male, USA, Chamberlain South, Dakota State, Lake Francis Case Elm Creek, 43°56'57"N, 99°31'40"W, 3.IX.1971, light trap, leg: Patrick l. Huson.

AR 2.58; frontal tubercles absent; posterior margin of tergite IX arc-shaped; anal point slightly constricted at base, wider at apex; superior volsella oval-shaped, covered with microtrichia at 1/3 distance from apex; inferior volsella completely covered by superior volsella; gonostylus straight, parallel-sided, tapering to the apex.

Male (n = 1).

Total length 4.47 mm. Wing length 2.02 mm. Total length/wing length 2.22. Wing length/length of profemur 2.16.

Coloration. Thorax yellowish brown. Femora of front legs yellowish brown, tibiae dark brown, tarsi lost; femora and tibiae of mid and hind legs light yellowish brown; mid and hind legs with tarsi I yellowish brown except for dark yellowish brown at both ends, tarsi II–V dark yellowish brown. Abdomen yellowish brown, hypopygium dark brown.

Head (Fig. 1B). Antenna with 11 flagellomeres, ultimate flagellomere 851 μm long. AR 2.58. Frontal tubercles absent. Temporal setae 20. Clypeus with 18 setae. Tentorium 177 μm long, 47 μm wide. Palpomere lengths (in μm): 36; 60; 179; 151; 203; Pm5/Pm3 1.13.

Figure 1. 

Cryptochironomus absum Liu, sp. nov., holotype male A wing B head C thorax. Scale bars: 200 μm.

Thorax (Fig. 1C). Antepronotals bare; acrostichals 8; dorsocentrals 9; prealars 5. Scutellum with 16 setae.

Wing (Figs 1A, 3C). VR 1.08. R with 22 setae, R₁ with 11 setae, R₄₊₅ with 17 setae. Brachiolum with three setae. Squama with 14 fringed setae.

Legs. Front tibia with three subapical setae, 143 μm, the remaining lost. Mid legs with two tibial spurs, 42 μm long, the other lost, tibial combs 34 μm and 56 μm wide. Hind legs with two tibial spurs, 23 μm and 42 μm long, tibial combs 44 μm and 87 μm wide. Tarsus I of mid leg with three sensilla chaetica; tarsus I of hind leg with three sensilla chaetica. Lengths (in μm) and proportions of legs as in Table 1.

Hypopygium (Figs 2, 3A, B, D, E). The posterior margin of tergite IX is arc-shaped and bears 32 setae, located dorsally and ventrally near the base of the anal point. Laterosternite IX has three setae. The anal point is 107 μm long, slightly constricted at the base, wider at the apex, and lacks lateral setae and microtrichia. The anal tergite bands are V-shaped and fused in the middle. The phallapodeme measures 134 μm long, and the transverse sternapodeme is 69 μm long. The superior volsella is oval-shaped, 56 μm long and 24 μm wide, covered with microtrichia at 1/3 distance from the apex, and has three long setae apically. The inferior volsella is finger-shaped, 22 μm long, bears two setae at the apex, is completely covered by the superior volsella, and lacks microtrichia. The gonocoxite measures 166 μm long and bears six strong setae along the inner margin. The gonostylus is 157 μm long, straight, parallel-sided, tapers to the apex, bears five setae along the inner margin, and has one single seta at the apex. HR 1.06. HV 2.85.

Figure 2. 

Cryptochironomus absum Liu, sp. nov., holotype male A hypopygium, dorsal view B hypopygium, ventral view C abdomen D anal point E superior volsella F inferior volsella. Scale bars: 50 μm (A, B, D–F); 500 μm (C).

Figure 3. 

Cryptochironomus absum Liu, sp. nov., holotype male A anal point B inferior volsella C wing D hypopygium, dorsal view E hypopygium, ventral view.

From the Latin, absum, absent, referring to the character of frontal tubercles absent, adjective in the nominative singular.

Cryptochironomus absum Liu, sp. nov. is similar to C. conus Mason, 1985 in having anal tergite bands, anal point, and superior volsella with similar shapes. However, it can be distinguished from C. conus by the following combination of characters: wing length of 2.02 mm, absence of frontal tubercles, inferior volsella with a finger-shaped appearance, and gonostylus straight in this new species. In contrast, C. conus has a wing length of 5.1–5.3 mm, distinct frontal tubercles, an inferior volsella with a tuberculate appearance and a protrusion at the base, and a curved gonostylus.

Holotype. one male, USA, New Mexico State, Rio Grande Otowi Bridge between Santa Fe and Los Alamos, 35°87'48"N, 99°31'40"W, 16.VII.1976, sweep net, leg: Melvin. Beard. Paratype. one male, North America, San Juan River at Farmington, 18.VII.1976, malaise trap, M. Beard.

Thorax pale yellow, with yellow-brown spots; anal point widest at base, constricted slightly at 1/3 distance from base, apically rounded; anal tergite bands V-shaped, fused in the middle; superior volsella oval-shaped, stretching upward at base, swelling at apex; inferior volsella columnar, ~ 2× as long as wide, with slender extension at base, bearing two long setae at apex, free microtrichia; gonostylus protruded at base, slightly curved in the middle, tapered to the apex.

Male (n = 2, unless stated).

Total length 5.03–5.10, 5.07 mm. Wing length 2.43–2.65, 2.54 mm. Total length/wing length 1.89–2.10, 2.00. Wing length/length of profemur 2.13 (1).

Coloration. Thorax pale yellow, with yellowish brown spots. Femora of front legs yellowish brown except for dark yellow-brown at ends, tibiae and tarsomeres dark brown; femora of mid and hind legs yellowish brown, tarsi I yellowish brown with dark brown in distal; tarsi II–V dark yellowish brown. Abdomen pale yellow, hypopygium yellowish brown.

Head (Figs 4B, 6A). Antenna with 11 flagellomeres, ultimate flagellomere 972 (1) μm long. AR 2.63 (1). Frontal tubercles conical, 18 μm high, 5 μm width at base. Temporal setae 17–18, 18. Clypeus with 12–18, 15 setae. Tentorium 167–173, 170 μm long, 45–50, 48 μm wide. Palpomere lengths of one specimen (in μm): 40; 61; 198; 171; 275; Pm5/Pm3 1.39.

Figure 4. 

Cryptochironomus beardi Liu, sp. nov., holotype male A wing B head C thorax. Scale bars: 200 μm.

Thorax (Fig. 4C). Antepronotals with three setae, acrostichals 6–9, 8; dorsocentrals 8–10, 9; prealars 6. Scutellum with 14 setae.

Wing (Figs 4A, 6D). VR 1.09. R with 26–28, 27 setae, R₁ with 19–22, 21 setae, R₄₊₅ with 22–25, 24 setae. Brachiolum with two setae. Squama with 8–9, 9 setae.

Legs. Front tibia with three subapical setae, 144 (1) μm, 151 (1) μm and 162 (1) μm. Combs of mid tibia 38–42, 40 μm wide with 22–27, 25 μm long spur, and 52–58, 55 μm wide with 30–40, 35 μm long spur; combs of hind tibia 47–48, 48 μm wide with 20–25, 23 μm long spur, 81–88, 85 μm wide with 38–42, 40 μm long spur. Tarsus I of mid leg with three sensilla chaetica. Tarsus I of hind leg with four sensilla chaetica. Lengths (in μm) and proportions of legs as in Table 2.

Hypopygium (Figs 5, 6B, C, E, F). The posterior margin of tergite IX is shoulder-shaped and bears 16–18, 17 setae located dorsally and ventrally near the base of the anal point. Laterosternite IX has 5–6, 6 lateral setae. The anal point is 70–80, 75 μm long, widest at the base, slightly constricted at 1/3 distance from the base, and apically rounded. The anal tergite bands are V-shaped and fused in the middle. The phallapodeme measures 113–115, 114 μm long, and the transverse sternapodeme is 57–61, 59 μm long. The superior volsella is oval-shaped, 45–50, 48 μm long, 22–29, 26 μm wide, stretching upward at the base, swelling at the apex, covered with microtrichia, and bears three strong setae at the apex. The inferior volsella is columnar, 25–31, 28 μm long, ~ 2× as long as wide, with a slender extension at the base, bearing two long setae at the apex, and lacking free microtrichia. The gonocoxite measures 151–164, 158 μm long and bears six strong setae along the inner margin. The gonostylus is 162–166, 164 μm long, widest and protruded at the base, slightly curved in the middle, tapered towards the apex, bears five short setae along the inner margin and one stronger seta at the apex.

Figure 5. 

Cryptochironomus beardi Liu, sp. nov., holotype male A hypopygium, dorsal view B hypopygium, ventral view C abdomen D anal point E superior volsella F inferior volsella. Scale bars: 50 μm (A, B, D–F); 500 μm (C).

Figure 6. 

Cryptochironomus beardi Liu, sp. nov., holotype male A frontal tubercles B anal point C inferior volsella D wing E hypopygium, dorsal view F hypopygium, ventral view.

Name after M. Beard, for the collector of the materials; noun in nominative case.

Cryptochironomus beardi Liu, sp. nov. resembles C. maculus Yan & Wang, 2016 in having gonostylus and inferior volsella with similar shapes. However, it can be distinguished from C. maculus by the following combination of characters: mid and hind legs with tarsi I yellowish brown base, dark brown distally, anal point apically rounded, superior volsella stretching upward, gonocoxite concave with gonostylus obviously in the former; whereas in C. maculus, the mid and hind legs have the tarsi I yellowish green with dark brown mark on basal portion, anal point apically pointed, superior volsella not stretching, gonocoxite fused with gonostylus completely.

Holotype. One male, USA, New Mexico State, Guadalupe County, Pecos River, Puerto de Luna below Diversion Dam, 33°04'06"N, 104°26'79"W, 20.VIII.1991, light trap, leg: Lensky & Doles. Paratypes. 8 males, USA, Guadalupe Country, Pecos River, Puerto de Luna below Diversion Dam, 20.VIII.1991, light trap, leg: Lensky & Doles.

Frontal tubercles conical; tergite IX saddle-shaped at the posterior margin; anal point parallel-sided with rounded apex; superior volsella crescent-like; inferior volsella finger-shaped, dentate at base; gonostylus curved slightly at 1/3 distance from base, swelling at distal 1/3.

Male (n = 9, unless stated).

Total length 4.58–5.30, 4.91 mm. Wing length 2.05–2.29, 2.16 mm. Total length/wing length 2.14–2.31, 2.26. Wing length/length of profemur 2.04–2.61, 2.23.

Coloration. Thorax yellowish brown. Femora of front legs yellowish brown, tibiae and tarsi dark brown; femora and tibiae of mid and hind legs yellowish brown, tarsi I yellowish brown, tarsi II–V yellowish brown to dark brown gradually. Abdomen yellowish brown, hypopygium dark brown.

Head (Figs 7B, 9A). Antenna with 11 flagellomeres, ultimate flagellomere 770–879, 829 (4) μm long. AR 2.48–2.76, 2.61 (4). Frontal tubercles conical, 20–31, 25 μm high, 12–16, 14 μm width at base. Temporal setae 15–21, 18. Clypeus with 10–16, 12 setae. Tentorium 115–170, 147 μm long, 30–46, 40 μm wide. Palpomere lengths (in μm): 33–47, 41; 52–76, 67; 136–174, 158; 140–157, 148; 201–232, 211; Pm5/Pm3 1.18–1.48, 1.35.

Figure 7. 

Cryptochironomus dentatus Liu, sp. nov., holotype male A wing B head C thorax. Scale bars: 200 μm.

Thorax (Fig. 7C). Antepronotals bare; acrostichals 5–8, 6; dorsocentrals 8–12, 10; prealars 4. Scutellum with 14–18, 16 setae.

Wing (Figs 7A, 9D). VR 1.08–1.12, 1.10. R with 14–18, 17 setae, R₁ with 12–15, 13 setae, R₄₊₅ with 19–25, 22 setae. Brachiolum with two setae. Squama with ten setae.

Legs. Front tibia with three subapical setae, 87–111, 98 (6) μm, 110–123, 115 (6) μm, 117–133, 124 μm. Combs of mid tibia 37–47, 43 μm wide with 23–34, 27 μm long spur, and 34–54, 46 μm wide with 32–45, 39 μm long spur; combs of hind tibia 30–49, 40 μm wide with 27–40, 31 μm long spur, 80–90, 83 μm wide with 34–48, 42 μm long spur. Tarsus I of mid leg with seven sensilla chaetica; tarsus I of hind leg with five sensilla chaetica. Lengths (in μm) and proportions of legs as in Table 3.

Hypopygium (Figs 8, 9B, C, E, F). The posterior margin of tergite IX is shoulder-shaped and bears 20–36, 30 setae. Laterosternite IX has 4–5, 4 setae. The anal point measures 77–87, 81 μm long and is parallel-sided with a rounded apex. The anal tergite bands are V-shaped and fused in the middle. The phallapodeme measures 115–135, 126 μm long, and the transverse sternapodeme is 64–90, 73 μm long. The superior volsella is crescent-like, 37–55, 48 μm long, 16–27, 21 μm wide, covered with microtrichia, and bears two strong setae at the apex. The inferior volsella is finger-shaped, 19–23, 21 μm long, dentate at the base, bearing two setae at the apex, and lacking free microtrichia. The gonocoxite measures 167–175, 170 μm long and bears five strong setae along the inner margin. The gonostylus is 150–157, 155 μm long, curved slightly at 1/3 distance from the base, swelling at the distal 1/3, with a small protrusion at the apex and bearing one apical seta. HR 1.08–1.12, 1.10. HV 2.96–3.38, 3.18.

Figure 8. 

Cryptochironomus dentatus Liu, sp. nov., holotype male A hypopygium, dorsal view B hypopygium, ventral view C abdomen D anal point E superior volsella F inferior volsella. Scale bars: 50 μm (A, B, D–F); 500 μm (C).

Figure 9. 

Cryptochironomus dentatus Liu, sp. nov., holotype male A frontal tubercles B anal point C inferior volsella D wing E hypopygium, dorsal view F hypopygium, ventral view.

From the Latin, dentatus, dentate, tooth-like, referring to the shape of the base of inferior volsella, adjective in the nominative singular.

Cryptochironomus dentatus Liu, sp. nov. bears resemblance to C. fulvus Johannsen, 1905 due to its similar frontal tubercles, anal point, and superior volsella. However, C. dentatus Liu, sp. nov. can be distinguished from C. fulvus by the following combination of characters: absence of spots on the thorax, tergite IX with a shoulder-shaped posterior margin, inferior volsella with a finger-shape and dentate base; whereas C. fulvus, has dark brown spots on the thorax, tergite IX with a conical posterior margin, and inferior volsella with a tuberculate and non-dentate base.

Holotype. One male, USA, South Dakota State, Springfield, Lewis and Clark Lake, Boat Basin, 42°87'33"N, 97°49'02"W, 13–17.VII.1964, leg: Pat Hadson. Paratypes. 3 males, Ohio, Cincinnati, Federal Water Quality Association, lab on the window, 26.X.1970, leg: W. T. Mason. 2 males, Springfield South Dakota, Boat Basin, Springfield, Lewist Clank Lake, 13–17.VII.1964, leg: Pat Hadson.

Tergite IX with slightly cone-like posterior margin; anal point narrow at basal 1/3, expanded at 1/3 of the apex, apically rounded; superior volsella crescent-like, with hook-like extension at the base, apically rounded; inferior volsella triangular widest at base, apex with a small protrusion; the junction of gonostylus and gonocoxite concaved obviously; gonostylus widest at basal 1/3, tapered to the apex.

Male (n = 6, unless stated).

Total length 3.29–3.91, 3.58 mm. Wing length 1.47–1.69, 1.61 mm. Total length/wing length 2.12–2.37, 2.23. Wing length/length of profemur 1.81–2.24, 2.02.

Coloration. Thorax yellowish brown. Femora of front legs yellowish brown, tibiae and tarsi lost; mid and hind legs yellowish brown. Abdomen pale yellow, hypopygium yellowish brown.

Head (Fig. 10B). Antenna with 11 flagellomeres, ultimate flagellomere 698–754, 724 (4) μm long. AR 2.29–2.49, 2.41 (4). Frontal tubercles absent. Temporal setae 14–17, 15. Clypeus with 12–18, 14 setae. Tentorium 126–153, 140 μm long, 31–37, 34 μm wide. Palpomere lengths (in μm): 21–36, 32; 41–56, 49; 126–155, 144; 114–144, 132; 174–232, 204; Pm5/Pm3 1.18–1.55, 1.40.

Figure 10. 

Cryptochironomus ferringtoni Liu, sp. nov., holotype male A wing B head C thorax. Scale bars: 200 μm.

Thorax (Fig. 10C). Antepronotals bare; acrostichals 4–7, 5; dorsocentrals 4–8, 7; prealars 4–5, 5. Scutellum with 8–14, 11 setae.

Wing (Figs 10A, 12C). VR 1.13–1.19, 1.16. R with 12–17, 15 setae, R₁ with 10–16, 14 setae, R₄₊₅ with 15–21, 19 setae. Brachiolum with 2–3, 2 setae. Squama bare.

Legs. Front tibia with three subapical setae, 113–132, 123 (3) μm, 124–127, 126 (3) μm, 128–144, 135 (3) μm. Mid legs with two spurs, 16–23, 20 μm and 20–34, 27 μm long, tibial comb 20–39, 30 μm and 27–40, 32 μm wide. Spurs of hind tibia 19–30, 26 μm and 30–45, 36 μm long, tibial comb 30–43, 36 μm and 50–83, 67 μm wide. Tarsus I of mid leg with 4–5, 4 sensilla chaetica, tarsus I of metapedes leg with 3–4, 4 sensilla chaetica. Lengths (in μm) and proportions of legs as in Table 4.

Hypopygium (Figs 11, 12A, B, D, E). The posterior margin of tergite IX is slightly cone-like and bears 12–20, 16 setae located dorsally and ventrally near the base of the anal point. Laterosternite IX has 3–6, 4 lateral setae. The anal point measures 55–63, 59 μm long and is contracted at the basal 1/3, expanded at the 1/3 of the apex, and apically rounded. The anal tergite bands are V-shaped and jointed medially. The phallapodeme measures 93–102, 96 μm long, and the transverse sternapodeme is 43–67, 54 μm long. The superior volsella is crescent-like, 35–39, 37 μm long, 18–27, 22 μm wide, with a hook-like extension at the base, apically rounded, and bears two strong setae at the apex. The inferior volsella is triangular, 12–15, 13 μm long, widest at the base, tapered towards the apex, with a small protrusion at the apex and bearing one seta. The gonocoxite measures 105–124, 116 μm long. The junction of the gonostylus and gonocoxite is distinctively concave. The gonostylus is 104–126, 115 μm long, widest at the basal 1/3, tapered to the apex, and bears one stronger seta at the apex. HR 0.96–1.06, 1.01. HV 2.92–3.33, 3.13.

Figure 11. 

Cryptochironomus ferringtoni Liu, sp. nov., holotype male A hypopygium, dorsal view B hypopygium, ventral view C abdomen D anal point E superior volsella F inferior volsella. Scale bars: 50 μm (A, B, D–F); 500 μm (C).

Figure 12. 

Cryptochironomus ferringtoni Liu, sp. nov., holotype male A anal point B inferior volsella C wing D hypopygium, dorsal view E hypopygium, ventral view.

Name after Dr. Leonard Charles Ferrington Jr., for his outstanding contribution to the knowledge of Chironomidae taxonomy; noun in nominative case.

Cryptochironomus ferringtoni Liu, sp. nov. bears resemblance to C. rostratus Kiffer, 1921 due to its similar shapes of the posterior margin of tergite IX and superior volsella. However, it can be distinguished from C. rostratus by the absence of frontal tubercles, contraction of the anal point at the basal 1/3 and expansion at the apical 1/3, and a triangular inferior volsella in C. ferringtoni Liu, sp. nov.; whereas C. rostratus frontal tubercles, a distally tapering or parallel-sided anal point, and a tuberculate inferior.

Holotype. one male, USA, New Mexico State, Catron Country, San Francisco River at Glenwood, 33°12'52"N, 109°28'01"W, 7.III.1976, reared, leg: Sta. H & M. Beard. Paratypes. 2 males, USA, New Mexico State, Catron Country, San Francisco River, 17.IX.1974, leg: M. Beard. 1 male, USA, New Mexico State, Catron Country, San Francisco River at Glenwood, 7.III.1976, reared, leg: Sta. H & M. Beard.

Thorax brown, with dark brown spots. Femora and tibiae of mid and hind legs dark brown at proximal and distal 1/5. The posterior margin of tergite IX cone-like; anal point slender, parallel-sided, apically rounded; superior volsella parallel-sided at base, slightly curved in the middle, widest at 1/3 distance from apex and apically swollen; inferior volsella thumb-like, with slight extension at base; gonostylus curved at 1/4 distance from base, parallel-sided towards apex, rounded apically.

Male (n = 4, unless stated).

Total length 4.24–5.05, 4.59 mm. Wing length 2.00–2.37, 2.12 mm. Total length/wing length 2.12–2.27, 2.17. Wing length/length of profemur 1.95–2.31, 2.20.

Coloration. Thorax brown, with dark brown spots. Femora and tibiae of front legs dark brown except for yellowish brown at distal 3/4, tarsi I dark brown except for yellowish brown at basal, tarsi II–V dark brown; femora and tibiae of mid and hind legs both dark brown at both proximal and distal 1/5, yellowish brown in the middle, tarsi I yellowish brown except for dark yellowish brown at apex, tarsi II–V dark yellowish brown. Abdomen yellowish brown, hypopygium dark yellowish brown.

Head (Figs 13B, 15A). Antenna with 11 flagellomeres, ultimate flagellomere 697–802, 746 μm long. AR 1.99–2.37, 2.17. Frontal tubercles conical, 15–23, 19 (3) μm high, 10–14, 13 (3) μm width at base. Temporal setae 16–23, 18. Clypeus with 14–18, 16 setae. Tentorium 115–144, 135 μm long, 39–42, 41 μm wide. Palpomere lengths (in μm): 34–49, 40; 73–84, 79; 156–176, 169; 132–142, 137; 191–225, 211; Pm5/Pm3 1.14–1.35, 1.26.

Figure 13. 

Cryptochironomus parallelus Liu, sp. nov., holotype male A wing B head C thorax. Scale bars: 200 μm.

Thorax (Fig. 13C). Antepronotals bare; acrostichals 5–10, 8; dorsocentrals 8–11, 10; prealars 4. Scutellum with 14–16, 15 setae.

Wing (Figs 13A, 15D). VR 1.02–1.09, 1.06. R with 10–18, 14 setae, R₁ with 6–10, 8 setae, R₄₊₅ with 10–15, 12 setae. Brachiolum with three setae. Squama with 10–17, 14 (2) setae.

Legs. Front tibia with three subapical setae, 114–121, 117.5 (2) μm, 129 (1) μm, 138 (1) μm. Combs of midtibia 41–57, 49 μm wide with 21–29, 24 μm long spur, and 42–61, 54 μm wide with 32–39, 35 μm long spur; combs of hind tibia 28–48, 36 μm wide with 28–36, 34 μm long spur, 80–92, 84 μm wide with 40–50, 44 μm long spur. Tarsus I of mid leg with three sensilla chaetica; tarsus I of hind leg with three sensilla chaetica. Lengths (in μm) and proportions of legs as in Table 5.

Hypopygium (Figs 14, 15B, C, E, F). The posterior margin of tergite IX is cone-like and bears ~ 22–36, 28 setae dorsally and ventrally near the base of the anal point. Laterosternite IX has 3–5, 4 setae. The anal point measures 54–65, 59 μm long and is slender with parallel sides, apically rounded. The anal tergite bands are V-shaped and show significant healing in the middle. The phallapodeme measures 103–120, 110 μm long, and the transverse sternapodeme is 56–89, 71 μm long. The superior volsella is 34–54, 47 μm long, 16–19, 17 μm wide, parallel-sided at the base, slightly curved in the middle, widest at the 1/3 distance from the apex, and apically swollen. It is covered with microtrichia and bears two strong setae at the apex. The inferior volsella is thumb-like, 15–20, 17 μm long, with a slight extension at the base and bears two setae at the apex. The gonocoxite measures 161–183, 176 μm long and bears seven strong setae along the inner margin. The gonostylus is 124–132, 127 μm long, curved at the 1/4 distance from the base, parallel-sided towards the apex, rounded apically, bears five short setae along the inner margin and one seta at the apex. HR 1.30–1.44, 1.38. HV 3.42–3.82, 3.60.

Figure 14. 

Cryptochironomus parallelus Liu, sp. nov., holotype male A hypopygium, dorsal view B hypopygium, ventral view C abdomen D anal point E superior volsella F inferior volsella. Scale bars: 50 μm (A, B, D–F); 500 μm (C).

Figure 15. 

Cryptochironomus parallelus Liu, sp. nov., holotype male A frontal tubercles B anal point C inferior volsella D wing E hypopygium, dorsal view F hypopygium, ventral view.

From the Latin parallelus, parallel-sided, referring to the character of anal point, adjective in the nominative singular.

Cryptochironomus parallelus Liu, sp. nov. resembles Cryptochironomus digitatus Malloch, 1915 and Cryptochironomus blarina Townes, 1945 by having similar shapes of the posterior margin of tergite IX, inferior volsella and gonostylus. However, it can be distinguished from C. digitatus by the following combination of characters: small frontal tubercles, AR 1.99–2.37, Wing length 2.00–2.37, 2.12 mm, anal point 54–65, 59 μm long and is slender with parallel sides, apically rounded in C. parallelus Liu, sp. nov.; whereas large frontal tubercles, AR 3.14–3.23, superior volsella with a hook-shaped base, and anal point constricted at the 1/3 distance from the base in C. digitatus; whereas large frontal tubercles, AR 3.7, Wing length 3.5 mm, anal point 230 μm long and is gradually tapered and pointed apically in C. blarina.

Holotype. one male, USA, New Mexico State, Colfax Country, Canadian River at Taylor Springs, 36°32'74"N, 104°49'22"W, 15.VII.1974, sweep net, leg: Sta. C. Paratypes. 2 males, New Mexico State, Colfax Country, Canadian River at Taylor Springs, 15.VII.1974, sweep net, leg: Sta. C.

Frontal tubercles absent; squama with 19 setae; anal point parallel-sided, slightly widening at apex; superior volsella crescent-like, with slender extension at the base, curved in the middle and apically swollen; inferior volsella triangular, widest at base, completely covered by superior volsella; gonostylus gradually tapered and pointed apically.

Male (n = 3, unless stated).

Total length 4.65–5.49, 5.01 mm. Wing length 2.31–2.59, 2.42 mm. Total length/wing length 1.98–2.12, 2.07. Wing length/length of profemur 2.00–2.79, 2.38.

Thorax light yellow-brown, with yellow-brown spots. Femora of front legs yellow-brown except for dark yellow-brown at both ends, tibia dark brown, tarsomeres lost; femora and tibiae of mid and hind legs yellow-brown, tarsus I–V yellow-brown to dark brown gradually. Abdomen yellow-brown, hypopygium dark brown.

Head (Fig. 16B). Antenna with 11 flagellomeres, ultimate flagellomere 861–1050, 980 μm long. AR 2.68–2.90, 2.82. Frontal tubercles absent. Temporal setae 16–18, 17. Clypeus with 15–17, 16 setae. Tentorium 131–176, 154 μm long, 50–61, 56 μm wide. Palpomere lengths of three specimens (in μm): 41–44, 43; 70–77, 74; 185–196, 191; 160–171, 166; 239–262, 251; Pm5/Pm3 1.29–1.34, 1.31.

Figure 16. 

Cryptochironomus taylorensis Liu, sp. nov., holotype male A wing B head C thorax. Scale bars: 200 μm.

Thorax (Fig. 16C). Antepronotals bare; dorsocentrals 8–10, 9; acrostichals 4–5, 5; prealars 5. Scutellum with 10–12, 11 setae.

Wing (Figs 16A, 18C). VR 1.05–1.11, 1.07. R with 15–18, 17 setae, R₁ with 16–20, 18 setae, R₄₊₅ with 21–22, 22 setae. Brachiolum with two setae. Squama with 19 (1) setae.

Legs. Fore leg bearing three subapical setae, 142 (1) μm, 144 (1) μm, 146 (1) μm long. Combs of mid tibia 40–60, 52 μm wide with 24–34, 29 μm long spur, and 45–69, 60 μm wide with 43–56, 49 μm long spur; combs of hind tibia 51–56, 53 μm wide with 34–39, 37 μm long spur, 97–105, 100 μm wide with 51–56, 53 μm long spur. Tarsus I of mid leg with 3–5, 4 sensilla chaetica; tarsus I of hind leg with 3–5, 4 sensilla chaetica. Lengths (in μm) and proportions of legs as in Table 6.

Hypopygium (Figs 17, 18A, B, D, E). The posterior margin of tergite IX is shoulder-shaped and bears 30–32, 31 setae at the base of the anal point. Laterosternite IX has 3–4, 4 setae. The anal point measures 91–103, 96 μm long and is parallel-sided, widening slightly at the apex. The anal tergite bands are fused and V-shaped. The phallapodeme measures 131–147, 139 μm long, and the transverse sternapodeme is 65–92, 78 μm long. The superior volsella is 60–63, 62 μm long, 18–23, 21 μm wide, crescent-like, with a slender extension at the base, curved in the middle and apically swollen, and has 3 long setae at the apex. The inferior volsella is triangular, 19–24, 22 μm long, widest at the base, completely covered by the superior volsella, with one apically seta and without microtrichia. The gonocoxite measures 174–184, 179 μm long and bears 30–32, 31 strong setae along the inner margin. The gonostylus is 169–192, 183 μm long, gradually tapered and pointed apically, and bears one seta at the apex. HR 0.93–1.03, 0.98. HV 2.47–2.89, 2.74.

Figure 17. 

Cryptochironomus taylorensis Liu, sp. nov., holotype male A hypopygium, dorsal view B hypopygium, ventral view C abdomen D anal point E superior volsella F inferior volsella. Scale bars: 50 μm (A, B, D–F); 500 μm (C).

Figure 18. 

Cryptochironomus taylorensis Liu, sp. nov., holotype male A anal point B inferior volsella C wing D hypopygium, dorsal view E hypopygium, ventral view.

Name after the type locality, the Canadian River at Taylor Springs; noun in nominative case.

Cryptochironomus taylorensis Liu, sp. nov. bears resemblance to C. curryi Mason, 1986 due to its similar shapes of the anal point, superior volsella, and anal tergite bands. However, it can be distinguished from C. curryi by the following combination of characters: R with 15–18 setae, inferior volsella triangular, and gonostylus pointed apically in this new species; whereas R with 40–46 setae, inferior volsella finger-shaped, and gonostylus rounded apically in C. curryi.