Silba srilanka McAlpine

Entirely black with white-fringed calyptrae
and pale-yellowish fumose wings in both sexes.
Male: Moderately large, somewhat smaller
than Lonchaea chorea Fab.; about 3.5 to
4.0 mm in length. Shining black from most
angles. Frons (Fig. 14) weakly shiny from
above, dull brownish-grey pruinose from below;
orbital plates shining blue-black; sides con¬
verging from vertex to a point just above
lunule, then gently diverging to bases of an¬
tennae; width at anterior ocellus about 1.2
times that at narrowst point C3-66:3.o);
length from anterior ocellus to lunule about
1.25 times as great as minimum width
(40:3.03, with about 10 reclinate inferior
orbital setulae, none of which arise above the
orbital bristle; with 4 to 6 rather strong (at
least as long and strong as setae on lunule}
interfiontal setulae in an arc immediately above
lunule; other interfrontal setulae weak and
hair-like. Ocellar triangle, in addition to pair
of strong ocellar bristles, with one supple¬
mentary setula just behind (above) anterior
ocellus and a pair of similar setulae just
behind and between posterior ocelli. Lu¬
nule with four stoutish setae on each side
near dorsal margin. Cheek narrow in side
view; at narrowest point, in ventral view,
about same width as third antennal segment,
with six oral setulae, the lowermost strongest,
and most outstanding. Antennae entirely
brownish-black, inner surface of second seg¬
ment, and inner base of third segment paler
brown, but not reddish. Third segment a little
more than 2.5 times as long as wide (10.5 : 4.0).
Greatest width of plumosity of arista about
.75 as wide as third antennal segment; arista with about twenty rays on dorsal and ventraJ
sides. Palpus broadly sausage-shaped with
numerous fine setulae; apex with one strange 1
bristle. Mesonotum mostly shining; lightly
pruinose from anterior dorsocentrals caudad
over dorsum of scutellum. Setulae short and
depressed. Chaetotaxy as in Lonchaea pectinella
except as follows: one humeral, prealai
(posthumeral) with several bristle-like hairs
adjacent to it, especially on inner side. Scutel¬
lum with two lateral and no apical setulae in
addition to usual four scutellar bristles (one
tiny setula present at apex of scutellum in
male from Sabaragamuwa). Epimeron with a
single, very weakly developed stigmatal bristle
Anepisternum with two strong anterodorsal
and three posterior bristles Katepisternum
with two bristles arising at practically same
level; no setuale arising directly above, behind,
or below them. Prosternum with several hairs
on each side anteriorly. Calyptrae and fringes
pale yellowish-white. Wing distinctly yellowish
fumose to naked eye. Veins yellow. Ratios ol
three sections of M2 (from base of first Mz to
apex), 6.5:7.8:10.1. Legs and tarsi entirely
blackish. Preapical dorsal bristle evident on all
tibia but at least three times as strong on mid
tibia as on the others. Mid tibia also with a
strong apical ventral bristle, i e., twice as strong
as dorsal one.
Abdomen shining black above. Epandriuin
(Figs. 18, 19) distinctly longer than high; with
a loose cluster of relatively strong bristles near
apex; inner apex of each surstylus with five
teeth on a lobe which is separated from median
lobe by a conspicuous notch; anterior lobe oi
surstylus strongly developed. Aedeagus very
long and very filamentous; without any proc¬
esses or spines on basal portion. Cerci rather
small and unmodified.
Female: As in male except for usual sexual
differences in width of frons and in the geni¬
talia. Ovipositor (Figs. 16, 17) moderately
stout, tapering to bluntly rounded apex. Apical
segment, nearly twice as long as broad; subbasal
dorsal hairs about equal to subapical ventral
ones; in addition with a pair of smaller hairs
mid-way along ventral surface, a subapical
dorsal pair and a lateral pair arising just distad
of the subapical dorsal ones