Australachalcus edwardsae, (VAN DUZEE), 2005

Pollet, Marc, 2005, Systematic revision of Neotropical Achalcus and a related new genus (Diptera: Dolichopodidae, Achalcinae) with comments on their phylogeny, ecology and zoogeography, Zoological Journal of the Linnean Society 143 (1), pp. 27-73 : 57-59

AUSTRALACHALCUS EDWARDSAE (VAN DUZEE)

COMB. NOV. ( FIGS 18 , 19 )

Achalcus edwardsae Van Duzee, 1930: 24

Enlinia edwardsae (Van Duzee), 1930: 24

Male. Small, rather stout species. Head. Face yellow, not as wide as ocellus, eyes almost touching. Frons dark brown. Occiput flat, dark brown, shining. Uppermost seven postoculars black, lower eight brownish. Palp small (1/5 of eye), triangular, yellow, infuscated at apex. Antenna entirely pale yellow with first flagellomere blunt-tipped, 1.1¥ as long as deep and 0.7¥ as long as scape and pedicel combined. Arista 2.1¥ as long as first three joints of antenna, inserted basodorsally on outer face, black with extreme base pale; with 1st segment very long and distinctly curving; with microscopic pubescence ( Fig. 18C ).

Thorax. Mesonotum and scutellum reddish yellow with brown spot on prescutellar depression extending upon scutellum. Pleura pale brown. Postnotum concolorous with mesonotum with frontolateral part pale brown with small black triangle, and large pale brown spot on dorsum. Metapleura with lower half white, uppermost half pale brown. Five ac, 1.5¥ as long as distance between rows. One small sutural bristle present.

Abdomen with tergites brown; 1st tergite paler and without dorsocentral marginal bristles; 2nd and 3rd sternites whitish with brown tinge, 4th and 5th pale brown, 5th sternite with caudal incision. Genital capsule pale brown. Hypopygium with apicoventrally spined hypandrium; aedeagus enlarged well before bifurcate apex; midventral bristle of surstylus simple ( Fig. 18F ); VEP evident, postgonites pale, DEP not evident; cercus small, elongate triangular ( Fig. 18E, G ).

Wing. Halter pale. Wing remarkable, very broad with eight distinct brown spots, with R 4+5 and M 1+2 curved, distinctly diverging. Proximal section of vein CuA 1 1.1¥ as long as apical section; CuAx ratio 2.1. Wing length 1.9–2.2 mm (n = 11) ( Fig. 18A ).

Legs including coxae yellowish white, with femora I and III and apical tarsomeres infuscated. Coxa I with very dense white microscopic pubescence. Trochanters slightly infuscated. Femur I greyish, with basal 1/3 white due to dense microscopic pubescence; with one erect ventral bristle, basad of row of 4–5 erect bristles in basal half, bristles about half as long as femur is deep; with one strong av and one strong pv preapical bristles ( Fig. 19 ). Femur II with one strong ad, inserted rather low, one rather strong av and one strong pv preapical bristles. Femur III yellowish white, pale brown on apical 3/5, with dark knee; with one strong ad and one strong av preapical bristles. Tibia I white, without dorsal bristles; tibia II with two strong ad and one strong pd bristles (1/6 of tibial length), ad bristles inserted at basal 1/5 and 3/5; tibia III with two moderately large ad, three moderately large pd bristles and 3–4 small erect ventral setae. Tarsus I with 1st to 3rd tarsomere white, 1st tarsomere infuscated on base, and 4th and 5th tarsomeres contrastingly black; tarsus II yellowish white with 5th tarsomere darker; tarsus III brownish yellow, contrastingly darker than tibia. First tarsomere of leg III 0.9¥ as long as 2nd tarsomere. Body length 1.4– 1.7 mm (n = 11).

Female. Considerably different from male. Face about as wide as ocellus. Palp ovoid, more than 1/4 of eye. Antenna with first three antennal joints infuscated, at least dorsally; 1st flagellomere entirely infuscated, 0.6¥ as long as deep and 0.6¥ as long as scape and pedicel combined; arista straight, 2.8¥ as long as first three joints of antenna ( Fig. 18D ). Abdomen with yellowish to dark brown tergites; sternites of 4th and 5th segment greyish brown, and of 6th segment dark brown; 7th and 8th segment shining, black brown, telescopic; apex of 8th segment reddish yellow, with eight short dornen; cercus brown, slender. Wing clear, with costal cell slightly infuscated; proximal section of CuA 1 1.8¥ as long as apical section; CuAx ratio 1.8 ( Fig. 18B ). Legs including trochanters whitish yellow, with femora slightly infuscated on apical half dorsally. Wing length 2.4–2.7 mm (n = 5).

probably the direct result of the shrivelled state of the antenna after mounting.

Figures

Figure 18. Australachalcus edwardsae (Van Duzee) (male, unless mentioned otherwise). A, wing; B, female wing; C, antenna; D, female antenna; E, hypopygium, lateral view; F, surstylus; G, hypopygium, dorsal view.

Figure 19. Australachalcus edwardsae (Van Duzee) (male). Leg I.