ART. 11. GENUS MESEMBRINELLA GIGLIO-TOS—-ALDRICH, Lh 
MESEMBRINELLA BRUNNIPES Surcouf. 
Mesembrinella brunnipes Surcour, Revis. Musc. Test., 1919, p. 78, female. 
Bolivia, Surinam. 
One of the type specimens from Bolivia, sent me for study by 
Professor Bezzi, shows the following characters. 
Female.—Head and thorax brownish, almost acorn colored, the scu- 
tellum the same. Cruciate bristles distinct. Antennae and palpi 
yellow, third antennal joint darkened from the arista on the outer 
side; facial ridges with numerous hairs above the vibrissae, but ascend- 
ing only as far as the lowest third of the third antennal joint. Meso- 
notum with whitish pollinose stripes, which when viewed from behind 
extend to the scutellum. Thoracic chaetotaxy: dorsocentral 2, 3; 
acrostichal 2, 3; humeral 3; posthumeral 2; presutural 2; notopleu- 
ral 2; supraalar 4 large and 1 or 2 small; intraalar 2; postalar 2; 
scutellum with 1 apical, 1 discal, laterals 1 large and 2 small; sterno- 
pleural 1, 1 on one side, 2, 1 on the other. 
Abdomen yellow at extreme base; at the middle of the first seg- 
ment it begins to be densely black haired, and at this point it becomes 
darker and takes on a purple reflection; this color and reflection ' 
increase apically, until the fourth segment is deep purple with no 
trace of yellow; tergites with no bristles except a few very weak 
on hind margin of second and third segments; sternites each with 
half a dozen of about the same size as those on the tergites. Legs 
dark brown, all the knees and apical half of middle and hind femora 
yellow; middle tibia with a stout flexor bristle beyond middle. 
Wings infuscated, most densely in a heavy subcostal stripe beginning 
just behind the tip of the first and not nearly reaching the third vein; 
anterior cross vein deeply infuscated and the same spot drawn out 
along the fourth vein, but not the third; fifth vein and hind cross 
vein also margined with brown. First posterior cell rather widely 
open before apex of wing. 
Length, 11.5 mm.; of wing, 12.5 mm. 
One female from Bolivia (Professor Johannsen) agrees with the type. 
MESEMBRINELLA PICTIPENNIS, new species. 
Male and female.—A brown species with deep blue or purplish 
abdomen greatly resembling brunnipes Surcouf, except in the follow- 
ing characters; there are three anterior dorsocentrals instead of two; 
one posterior acrostichal instead of three; three supraalar instead of 
four; the wing is much darker; apical cell broader and more widely 
open. The color of the wing, which is the same in both sexes, is 
considerably different from that of brunnipes. 
In pictipennis the wing is wholly infuscated beyond the small 
cross vein, except a slight yellow mark beyond the tip of the first vein 
and another very small beyond the tip of the second vein. The 
broad apical cell is somewhat lighter in the middle, especiallv in the 
