84 Tur BLowFrures or NortH AMERICA 
ments each with a marginal row of weak bristles; fifth sternite 
with a V-shaped incision and with black hair. 
Genital segments comparatively small, dark brown, with 
black hair, lying almost parallel with sternites. Internal fea- 
tures as illustrated (pl. 18,,C, D, and E). 
Female. Head height 17.4; eye height 13.6; bueca 0.22 of 
eye height; length at vibrissa and at antennal base 10.0; width 
21.0; frontale orange to red orange, occupying three-fifths of 
frontal space, the margins nearly parallel; frontal row con- 
sisting of about 12 bristles, only the anterior 4 or 5 large; 
front at narrowest (at vertex) 0.26 of head width, the margins 
nearly parallel or but slightly divergent, these flaring outward 
anteriorly to 0.82 of head width at lunule, with a few brownish 
hairs outside the frontal rows; third antennal segment twice as 
long as second; vibrissae set 4.6 apart; parafaciale 2.6 in width 
opposite lunule; palpus 6.0 in length; vertex orange brown, 
golden brown pollinose. Wing (pl. 8, H) with costal sections 
2 to 6 in the proportions 145 :160:180:80:45. Otherwise similar 
to male except for normal sexual differences. 
Length. 18-15 mm. 
Distribution. Neotropical: Costa Rica, south to northern 
South America. 
As pointed out by Aldrich (1922), some specimens placed 
under this name have fulvous hairs on the pleura, coxae, femora, 
and tibiae. 
Huascaromusca uniseta (Aldrich), new combination 
Mesembrinella uniseta Aldrich, U.S. Natl. Mus. Proe. 66(18) :13- 
14, 1925. (Type, male from La Suiza de Turrialba, Costa 
Rica, No. 26797, U. S. National Museum.) 
A blue-black species with dark brown to black legs, hyaline 
wings; the face, anterior portion of bucca, palpi, and thoracic 
spiracles bright orange. . 
Male. Head width 12.8; length at antenna 7.0 and at vibrissa 
6.0; eye height 10.0; head height 10.8; bucea orange anteriorly, 
black posteriorly, 0.10 of eye height, with dark hair only; 
frontale red orange on anterior third, black at vertex, and twice 
aS wide as parafrontale at narrowest; frontal row of bristles 
extending anteriorly to nearly opposite base of second antennal 
segment but not extending posteriorly beyond the narrowest 
portion of the front, consisting of about six bristles; parafrontale 
black, silvery pollinose, bare; front at narrowest 0.14 of head 
width, 0.19 at vertex, and 0.25 at lunule; vertex black, slightly 
silvery, parafaciale orange, golden pollinose, 1.2 in width oppo- 
