SUBFAMILY MESEMBRINELLINAE 85 
site lunule and narrowing below; clypeus red orange, silvery 
pollinose; vibrissae only slightly above the oral margin and set 
3.6 apart; faciale rather flattened, with only a few short setae 
above vibrissa; antenna orange, third segment three times as 
long as second; arista orange at base, dark brown to black 
apically, with black ciliation nearly to apex; back of head black, 
silvery pollinose, with two or three rows of postocular cilia and 
with yellow-orange hair which is particularly noticeable below. 
Thorax indistinetly striped, with thin whitish pollen that is 
visible from a posterior view mainly; all lesser thoracic hair 
black; preacrostichal bristles two, the posterior one 2.4 before 
the suture; hindmost predorsocentral bristle 2.2 before the 
suture; postacrostichal bristles two; sternopleural bristles three; 
prosternum with black setae laterally and yellow hair in middle; 
selerites at wing base dark brown to black; thoracic spiracles 
with orange hair, the metathoracic spiracle with long black hairs 
on the ventral margin; under surface of scutellum with brown 
hair laterally, and with one lateral bristle and a weak bristle 
just anterior to it; postscutellar plates with black setae. 
Legs as in bicolor except with longer hair, this more abundant 
on the middle and hind femora, particularly on the anteroven- 
tral and posteroventral surfaces. 
Wing (pl 8, I) hyaline, slightly infuseated basally and at 
cross veins; basicosta and subcostal sclerite orange brown, the 
latter darker and with brown pubescence; costal sections 2 to 6 
in the proportions 80:60 :100:84:12; squamal lobes orange brown 
to brown, the rims darker. 
Abdomen blue black with purple reflections, whitish pollinose 
anteriorly and ventrally in certain lights; first and second seg- 
ments each with one lateral bristle; third segment with a mar- 
ginal row of long strong erect bristles; fourth segment with a 
distal row of from four to six bristles, and with a marginal row 
of weaker bristles; sternites black, fifth as illustrated (pl. 14, B). 
Genital segments large, black, shining, with black hair. In- 
ternal features (pl. 14, A and C) as illustrated. 
Female. Head height 10.4; width 13.0; eye height 9.0; bucca 
0.20 of eye height; length at antenna 7.4 and at vibrissa 6.0; 
parafaciale 1.6 opposite lunule; distance between vibrissae 3.6; 
frontal 2.0 times as wide as parafrontale anteriorly and wider 
toward vertex, orange red on anterior half, black posteriorly; 
frontal row of bristles not extending posteriorly beyond middle, 
composed of about four bristles; only one proclinate and one 
reclinate frontoorbital bristle; front at vertex 0.25 of head width, 
the margins nearly parallel to within one unit of lunule, then 
