Achalcus niger, Pollet, 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 : 44-45

ACHALCUS NIGER SP. NOV. ( FIG. 9 )

Male. Rather small, stout species. Head. Face brownish black, 1.5¥ as wide as ocellus; clypeus with dense white pubescence. Frons brownish black. Occiput concave, shining brownish black. Uppermost four postocular bristles dark, lower seven paler (brownish). Palp small (less than 1/5 of eye), broad ovoid, dark brown. Antenna almost entirely brown with lower half of pedicel paler on inner face and extreme basis of first flagellomere somewhat paler; latter triangular, 1.8¥ as long as deep and 1.6¥ as long as scape and pedicel combined. Arista 1.2¥ as long as first three joints of antenna, distinctly apical, with microscopic pubescence ( Fig. 9B ).

Thorax including pleura and metapleura dark to blackish brown, shining. Postnotum with distinct frontolateral black triangle. Six ac, 1.5¥ as long as distance between rows. One very small sutural bristle present.

Abdomen with tergites including genital capsule dark brown, shining. Sternites greyish brown. Hypopygium. Aedeagus with subapical dorsal bend; ventral bristle of surstylus with small apical flag; VEP and DEP evident; postgonites darkened at apex; cercus moderately developed, elongate ( Fig. 9C ).

Wing. [Halter lacking]. Wing pale with R 4+5 and M 1+2 clearly diverging. Proximal section of vein CuA 1 2.3¥ as long as apical section, latter 1.6¥ as long as outer crossvein. Wing length 2.2 mm ( Fig. 9A ).

Legs largely yellow with coxa I brown with anterior and inner half pale yellow, coxa II and III dark brown, former paler on posterior half. Trochanter of leg I pale, of leg II and III brown. Femur I slightly infuscated dorsally, femur III brownish yellow. Femur I without erect basoventral bristle and with two av and two pv preapical bristles. Femur II with one strong ad, one small av and one strong pv preapical bristles. Femur III with one strong ad and one strong av preapical

Figures

Figure 9. Achalcus niger sp. nov. (male). A, wing; B, antenna; C, hypopgyium.