Silba setifera
Remarks. Males of Silba setifera are easily distinguished from related species b]
the cluster of long incurved hairs at the apex of the abdomen. In both sexes the base o
the antennae, especially the inner base of the third segment, is bright orange-red. Th
genitalia, particularly the aedeagus, and to a lesser degree the ovipositor, are ver
distinctive.
Male. Frons about 1.3 times as long as wide (10 1 7 4) Inferior orbital setulae about 20, in a
uniform, uninterrupted row Posterior ocelli distinctly closer to each other than to anterior ocellus; ocellar
triangle with 2 tiny setulae m front of posterior ocelli, in addition to ocellar bristles, and another larger pair
immediately behind and between posterior ocelli. Lunule orange-brown m ground colour, with 5 setulae on
each half First and second antennal segments mostly orange-brown Third segment bright, orange-brown on
basal third, about 2 5 times as long as wide (10 0 4 0) Phimosity of arista about 75 as wide as third antennal
segment
Prumosity of posterior part of mesonotum, disc of scutellum, and basal half of abdomen, with a brassy
tint Scutellum with only 2 lateral setulae on each side in addition to the usual bristles (this number varies
from 2 to 5 in the species) Stigmal space of wmg about half as long as maximum width of costal cell
(1 0 2 0) Ratios of three mam sections of Mz beyond base of discal cell, 6 0'7 0 9 5 Long hairs in cluster on
each side of apex of abdomen, longer, stronger and more outstanding than in my illustration (McAIpme 1956,
fig 41), genitalia as illustrated by me (1956, figs 38-40) Surstylus with 5 teeth. Aedeagus 1-segmented,
somewhat swollen in middle, especially in ventral view, and rather suddenly bent at this point in lateral view
Female. Agreeing with male except m usual sexual characters Frons slightly broader than long
(11 1:10 0) Third antennal segment brighter reddish brown at base, especially on inner surface, about 2 4
times as long as wide (10 0'4 1) Ovipositor (Figs. 44, 45) very slender Apical segment fully 3 times as long
as greatest width, with rounded apex, subbasal dorsal hairs scarcely as long and strong as subapical ventra
hairs