Silba longigonite
Description: Male. Head: Eyes bare. Frons sub-shining black, frontal and interfrontal
setulae very short, less than 0.1× length of orbital setae, a few longer setulae
on anterior margin. Orbital plates shining, bare apart from orbital seta. Lunule,
ground colour dark, when seen from above lunule, parafacials and face lightly silver
pollinose.
Anterior genal setulae in a single row of six along mouth margin, stronger
basally but these not noticeably stronger than other setulae on genae. Antennae black;
postpedicel
slightly orange at extreme medial base, length to depth ratio 2.6:1. Arista
plumose, ratio of plumosity at maximum extent to depth of postpedicel 1:1. Thorax: Scutum shining blue-black. Anepisternum with four anterior setae (one
of these on right side is rather weak) and three rather long, curving posterior setae.
Katepisternum with two setae located near dorsal margin, anterior only slightly
shorter and weaker than posterior. Scutellum, on margin between lateral and apical
setae, with three setulae on each side, two between apical setae. Calypteres
entirely
pale, with a uniform pale fringe. Wings clear, veins brownish, wing length
4.0 mm. Legs brown, contrasting with black setulae, tarsomeres appearing darker
due to density
of setulae.
Male terminalia: Epandrium in lateral view rather circular, slightly wider than
high, with numerous setulae on posterior and ventral surfaces. Cerci small, 0.3×
height of epandrium, not sclerotized, bearing numerous rather stiff setulae, these
thicker and shorter on ventral surface. Surstylus contained within shell of epandrium,
inner surface with three well-spaced prensisetae along posterior margin, a single row
of relatively long setulae along ventral margin with a slightly multiserial row lying
just anterior to these, a pair of stiff setulae situated centrally below base of cerci.
Pregonites long and finger like, directed posteriorly at apex, setulose basally with
a small lateral process on outer surface. Postgonites large with setulose margins.
Phallus simple U-shaped.