ART. 11. GENUS MESEMBRINELLA GIGLIO-TOS——ALDRICH. 15 
saw in two genera, and hence failed to perceive the identity of the 
two species named bicolor. This is by far the commonest species of 
the genus, and has a wide range. 
MESEMBRINELLA BATESI, new species. 
Female.—A brown species with only slight metallic tinge on the 
abdomen, the pale abdominal pollen arranged in small, short, trans- 
verse “‘ripple marks.”’ 
Head light yellow, darker at vertex, the entire orbit with white 
pollen; front rather wide for the genus. Thorax acorn colored above, 
more yellow on sides. Chaetotaxy: acrostichal 2, 1; dorsocentral 
2, 3; humeral 3; interhumeral 1; posthumeral 2; presutural 2; 
supraalar 4; intraalar 2; postalar 2; scutellar 1 apical, 1 and a 
small lateral, 1 discal; sternopleural 1, 1. 
Abdomen with less metallic reflection than any other species except 
facialis, while the ripple marks above mentioned are not found in 
any other species that I have seen; they seem to originate from 
small pollinose dots at the base of the hairs, which coalesce in minute 
and short transverse rows; they occur even upon the small fifth seg- 
ment. Third segment with very weak and depressed marginal 
bristles, those of fourth little stronger. Legs yellow, middle and 
hind tibiae with a trace of infuscation. Wings hardly infuscated 
except for the heavy subcostal dark stripe; apical cell not very wide 
for the genus, its costal opening less than half as long as the preced- 
ing costal segment. 
Length, 12 mm. 
One female, Amazon River, 65.53, collected by H. W. Bates. 
Type in the British Museum. 
MESEMBRINELLA CRUCIATA Townsend. 
Huascaromusca cruciata TOWNSEND, Insecutor Ins. Menst., vol. 6, 1918, p. 155. 
Female (type).—Black except antennae, palpi, and front of head, 
which are yellow. Front narrow for a female, about 0.22 of the head 
width, at vertex, not much wider at antennae, moderately wider 
below; head black above to about middle of front, thence yellow to 
lower curve of eye or more, gradually changing color in both regions; 
ocellars, orbitals, and frontals large; the next bristle above the usual 
two orbitals is in the frontal series, turned laterally, above this the 
strong, reclinate vertical (not as given by Townsend, with three or- 
bitals); a pair of cruciate bristles in the frontal stripe below the ocelli; 
third antennal joint more than twice the second. 
Thorax dull black with slight cinereous pruinosity, more pollinose 
at extreme front edge; bristles long and erect. Chaetotaxy: dorso- 
central 2, 3; acrostichal 2, 1; humeral 3; posthumeral 2; presu- 
tural 1; notopleural 2; supraalar 3; intraalar 2; postalar 3; scutellar 
