SUBFAMILY MESEMBRINELLINAE 17 
Abdomen bluish purple, the first segment orange except at 
the posterior margin, where it is narrowly dark on dorsum and 
more widely dark laterally; second segment slightly yellow 
basally on sides; first and second segments each with one lateral 
bristle; third segment dark metalle purplish, with a marginal 
row of strong erect bristles; fourth segment with a marginal 
row of weaker bristles. 
Genital segments orange brown, of medium size, and with 
erect black hair. Internal anatomical features (pl. 12, A and B) 
as illustrated. 
Female. Head width 13.4; height 11.2; eye height 9.1; bucca 
0.20 of eye height; length at antenna 6.5, and at vibrissa 6.3; 
parafaciale 1.4 in width opposite lunule; distance between vibris- 
sae 3.4; front at narrowest (at vertex) 0.22 of head width, 0.29 
at lunule, the margins but slightly divergent, anteriorly brown 
with brownish pollen toward vertex; third segment of antenna 
2.6 times as long as second; palpus 3.3 in length. Thorax with 
whitish dorsal longitudinal stripes outside acrostichal rows of 
bristles, these extending slightly beyond suture. Wing with 
costal sections 2 to 6 in the proportion 95:70:120:100:13. Other- 
wise similar to male except for normal sexual differences. 
Length. 7.0-8.5 mm. 
The type series, collected from February 8 to July 26, 1923, 
by Pablo Schild, are the only specimens known to me. Three 
paratypes, one male and two females, are in the National 
Museum. The above descriptions are based upon these specimens. 
Huascaromusca formosa (Aldrich), new combination 
Mesembrinella formosa Aldrich, Wash. Ent. Soc. Proc. 34:25, 
1932. (Type, male from Santa Emilia, Pochuta, Guatemala, 
in the collection of J. Bequaert of Harvard University.) 
An orange and brown species which has the apical portion of 
the abdomen metallic blue. 
This species differs from flavicrura, which is apparently the 
most closely related described species, by having but one pre- 
acrostichal bristle, the antennae partially blackish, the epistoma 
not prominent, the pleura and tibiae more yellowish, and the 
front of the female considerably wider in comparison to the 
head width. 
Male. Not seen. Described by Aldrich as having eyes nearly 
contiguous, front at narrowest only half as wide as anterior ocel- 
lus; parafaciale and postorbit with silvery-white pollen which 
is nearly imperceptible on buceca with the yellow ground color 
s 
