18 PROCEEDINGS OF THE NATIONAL MUSEUM. VOL. 62. 
or almost no reflections. Front one-fifth head width, orbital bristles 
distinct; facial ridges distinctly high all the way up, with numerous 
short, black hairs up to the middle of the third antennal joint. 
Thorax with the usual pollinose stripes not very distinct. Chaeto- 
taxy: acrostichal 2, 1 (the prescutellar as large as the adjacent 
dorsocentrals); dorsocentral 2, 3; humeral 2; posthumeral 2; pre- 
sutural 1; notopleural 2; supraalar 3; intraalar 2; postalar 2; sterno- 
pleural 2, 1; scutellum with 1 apical, 2 lateral, 1 discal. The hind 
calypter along its attaching membrane bears black hairs, close to the 
thorax, none on its disk. 
Abdomen short, globose, with almost no metallic reflections what- 
ever; fourth segment covered with brown pollen; first segment with- 
out bristles, second with one lateral, third and fourth with a marginal 
row of a dozen, fifth also with a distinct row above. Sternites wide, 
each bearing a complete apical row of six and a broken subbasal of 
about four short, spiny bristles. 
Wings rather uniformly infuscated, second costal segment two- 
thirds as long as the third. 
Length, 9.2 mm. 
One female, Higuito, Costa Rica (Pablo Schild). 
Type.—Female, Cat. No. 25248, U.S.N.M. 
MESEMBRINELLA PAUCISETA, new species. 
Female.—Head and thorax, base of abdomen, coxae, femora, and 
front tibiae yellowish brown; dorsum of thorax rather dark brown; 
middle and hind tibiae infuscated, the former darkest, almost black. 
Antennae, palpi, and proboscis yellow. Abdomen with narrow violet 
posterior bands on segments 2 and 3, presumably also on 4, but it is 
soiled. Pollinose stripes distinct in front on thorax as in bicolor. 
Chaetotaxy: acrostichal 0, 1; dorsocentral 2, 3; humeral 2; post- 
humeral 1; presutural 1; notopleural 2; supraalar 3; intraalar 1; 
postalar 2; sternopleural 1, 1; scutellum with 1 apical, 1 lateral, 1 
discal. Abdomen with a distinct median marginal pair and a lateral 
on the third segment, on the fourth a few smaller at tip. 
Wings lightly infuscated, with a dark stripe between costa and 
third vein on apical half; first posterior cell intercepting a portion 
of the costa about equal to the anterior cross vein. 
Length, 10 mm. 
One female, near Para, Brazil (Miss H. B. Merrill). 
Type.—Female, Cat. No. 25249, U.S.N.M. 
MESEMBRINELLA CYANEICINCTA Surcouf. 
Ochromyia cyaneicincta Surcour, Revis. Musc. Testaceae, 1919, p. 69, female. 
This species, which I have not seen, is said by Surcouf to be almost 
like aeneiventris Wiedemann, differing, however, in having no abdom- 
