Acomoptera plexipus (Garrett)

Kerr, Peter H., 2011, Six new species of Acomoptera from North America (Diptera, Mycetophilidae), ZooKeys 137, pp. 41-76 : 60-64

Acomoptera plexipus (Garrett) Figs 2123

Eudicrana plexipus Garrett 1925: 4

Type Material.

Holotype examined: ♀, "Vancouver, B.C., 27.3.15 / wing 2693 / HOLOTYPE, Eudicrana plexipus, Garrett, CNC No7849 / MONOTYPE EUDICRANA PERPLEXUS ♀ <signature> C.B.D. Garrett " [CNC]. Specimen dissected, with female genitalia retained in glass vial pinned below specimen. Specimen in bad condition, covered with fungal spores (Fig. 21B).

Material Examined.

1 ♂, "Mt. Thornhill Terrace, B.C., 26-VII 1960, C.H. Mann / along trail in hemlock forest 2500' / 11G478 <dissection card>" [54.532°N, - 128.567°W; CNC]; 1 ♂, "Johnston Canyon, 4700' Banff, ALTA., 18 July, 1962, W.R.M. Mason / 11G490 <dissection card>" [51.237°N, - 115.855°W; CNC]; 1 ♂, "Ont., Iroquois Falls, 30.vi.1987, J.R. Vockeroth / Populus-Picea wood; rich un dergrowth " [48.768°N, - 80.673°W; CNC]; 1 ♂, "N.S., CBHNt.Pk., PG706863, 2.VI.1984, B.E. Cooper" [46.738°N, - 60.650°W; CNC]; 1 ♂, "N.S., CBHNt.Pk., Mackenzie Mt., 400m PG639848, 7.VI.1983 / birch & fir, B.E. Cooper" [46.738°N, - 60.650°W; CNC]; 1 ♂, "N.B., Victoria Co., 1982, G.R.Parker" [CNC].

Diagnosis.

This species is easily distinguished from all other Acomoptera in having a short preapical hook arising from the gonocoxites ventromedially (Figs 23 B–C, 23E); a narrow, bifid process arising from the gonocoxites dorsomedially (Figs 23A, 23C); and the unique form of the gonostylus (Figs 22, 23 A–B, 23 D–E).

Description.

Male. Body length (n=4): 5.0-6.1 mm (avg = 5.8 mm). Wing length: 4.7-5.8 mm (avg = 5.3 mm).

Coloration (Fig. 21). Head brown; palpomeres yellowish darkening to brown distally or brown throughout. Antennal scape and pedicel brown; base of first flage llomere yellowish, otherwise flagellomeres brown. Thorax mostly brown, with some lighter areas (e.g., mediotergite); scutum brown to dark brown; darker in areas of acrostichal and dorsocentral setae, scutum setae gold- or golden brown-colored. Legs becoming increasingly brown towards tarsi, coxae cream-colored; femur yellowish or cream-colored, tibia yellowish brown to brown, tarsi brown; hind legs lighter in color. Wing hyaline without markings, wing veins brown; haltere cream-colored to light brown. Abdominal segments concolorous brown, with predominantly light, golden setae. Terminalia mostly brown, except gonostyli yellowish.

Head. Ocelli slightly raised; middle ocellus approximately same size as lateral ocelli, lateral ocellus located approx. width of ocellus or slightly less from eye margin, separated from median ocellus by approx. twice its own diameter. Eyes with numerous microsetae, longest approx. twice as long as width of facet. Face with mostly brown setae, longest of which approx. same length as width of face. Antenna approximately 2/3rds length of abdomen. Palpus approx. 1 × width of head (anterior view); palpomere 2 short, as wide as long, remaining palpomeres longer than wide; palpomere 4 approx. 4 × longer than wide; palpomere 5 approx. 7 × longer than wide, subequal to or shorter than combined length of palpomeres 3 and 4.

Thorax. Antepronotum bearing setae; remaining thoracic sclerites bare. Wing venation similar to others in the genus (e.g., Acomoptera digitata sp. n., Fig. 8), may exhibit teratological variations (e.g., loss of R4 (Fig. 21; in this specimen, R4 lost on left wing but present on right wing)); costal vein extends beyond R5, approx. 0.3 × distance between R5 and M1; R1, R5, and M1 with at least some setae on lower surface.

Male Genitalia (Figs 22-23). Epandrium approx. 1.7 × wider than long (Fig. 23F). Gonocoxites with dorsomedial fork (Figs 23A, 23C) and short ventral hook (Figs 23 B–C, 23E). Gonostylus complex, as shown in Figs 22, 23 A–B, 23 D–E.

Female as described by Vockeroth (1980).