Australachalcus brevinervis, (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 : 53-54

AUSTRALACHALCUS BREVINERVIS (VAN DUZEE)

COMB. NOV. ( FIG. 15 )

Achalcus brevinervis Van Duzee, 1930: 23

Male. Rather large, slender species. Head. Face blackish brown, dusted, about 2¥ as wide as ocellus. Frons dark brown. Occiput with central dorsal concavity, dark brown, shining. Palp ovoid circular, about 1/4 of eye size, dark brown. Antenna almost entirely dark brown with pedicel yellowish brown on inner face; first flagellomere elongate triangular and 1.2¥ as long as scape and pedicel combined. Arista as long as first three joints of antenna, distinctly subapical.

Thorax almost entirely dark brown with small parts of alar and postalar areas and lateral parts of scutellum yellowish. Seven ac, 2¥ as long as distance between rows. One strong sutural bristle present.

Abdomen with five pubescent segments. Abdominal tergites including genital capsule entirely shining dark brown, with strong marginal bristles, especially on 1st tergite. Sternites entirely brown. Genital capsule small. Hypopygium with apicoventrally spined hypandrium; aedeagus long and gently curved ventrally; ventral bristle of surstylus with apical flag; VEP and DEP evident; postgonites robust and dark; cercus very long and tapering, with curved marginal bristles ( Fig. 15 ).

Wing. Halter small and pale. Wing slightly darkened with vein CuA 1 stronger than other veins; vein R 4+5 slightly curved and M 1+2 straight, both parallel at wing apex. Proximal section of vein CuA 1 7.5¥ as long as apical section, CuAx ratio 0.4¥. Wing length 3.3 mm.

Legs mainly dark yellow with darker coxae. Coxa I brownish yellow, infuscated anteriorly with pale pubescence, coxa II mainly brown, and coxa III dark yellow, slightly infuscated. Trochanters dark yellow. Femur I and II yellow and femur III dark yellow, all broadly infuscated along whole length dorsally. Femur I with erect basoventral bristle, 0.7¥ as long as femur is deep, basad of row of very strong, erect av bristles; with one row of erect pv bristles, not as long as femur is deep; with one pv preapical bristle. Femur II with one strong ad preapical bristle; with one row of very strong (basal ones 2/3 of femur depth) erect av bristles, and one row of smaller erect pv bristles on less than apical half; av and pv bristles of femur I and II decreasing in length towards apex. Femur III with one weak ad, inserted just above lower 1/3 of femur, and two very strong av preapical bristles; with one row of thin av bristles along whole length, increasing in length towards apex; with one row of very strong erect pv bristles, bristles in basal half longer than femur is deep. Tibia I dark yellow, without dorsal bristles, with short ventral pubescence; tibia II and III yellow, tibia II with two moderate ad and one moderate pd bristles, basal bristles forming no ad-pd couple; with dense and long (longer than tibial depth) erect ventral pubescence along whole length; tibia III with three strong ad, four strong pd bristles and about 20 strong pv setae. Tarsus I and II brown with 5th tarsomeres almost black, tarsus III dark brown; tarsus II and III with 1st tarsomere pale on extreme base. First tarsomere of leg III as long as 2nd tarsomere.

Holotype. 1♂, CHILE: Region de los Lagos, Prov. Llanquihue, Puerto Montt, 24.xii.1926 (F. & M. Edwards) ( BMNH; D, hypopygium mounted), examined. Labels: ‘ Puerto Montt 24.XII.1926 Y’/‘ S. Chile: Llanquihue prov. F. & M. Edwards BM 1927–63’/ ‘ Achalcus brevinervis HOLOTYPE Van Duzee’.

Figures

Figure 15. Australachalcus brevinervis (Van Duzee) (male). Hypopygium with cercus separated.