1910] Melander — The Genus Tachydromia 59 
scutellum with four black bristles; acrostichal and dorsocentral bristles 
microscopic; hypopygium large, flexed to the right. 
Front narrowly V-shaped, cinereous; ocelli large, ocellar bristles present, 
black; first antennal joint testaceous, the outer joint fuscous, pubescent, 
arista subterminal, pubescent, four times the length of the antenna. Eyes 
completely contiguous on the face, facets uniform. Palpi twice as long as 
broad, sericeous, testaceous. Proboscis slender, vertical, piceous, one-half 
the height of the head. Occiput and entire thorax rather lightly covered with 
cinereous pollen; humeri comparatively small and not so deeply constricted 
as in the other species; the usual black bristles present along the sides of the 
notum; scutellum with two long decussating and two short bristles; acro- 
stichal and dorsocentral rows of minute whitish bristles present, with about 
six bristles to each row, the last dorsocentral large; no pleural hairs. Ab- 
domen brown-black, sub-shining, last segments black hairy; hypopygium 
large, globular, flexed to the right. Coxae shining yellowish, legs yellowish, 
femora dusky on the outer half, legs provided with short white bristly hairs, 
middle tibiae with series of minute black setulae beneath, front femora much 
thicker than the others. Halteres dusky. Wings clear hyaline, veins strong, 
hind margin ciliate; first posterior cell ending at wing tip, and there somewhat 
contracted, marginal cell a little longer than the submarginal along the costa. 
Described from a single specimen labeled, Grenada, W. I., received 
from Prof. J. M. Aldrich. 
Tachydromia agens sp. nov. 
Male and female. Length 1.3 mm. Head and thorax pruinose, legs dark 
fuscous, wings clear hyaline; antennae blackish; palpi sub-quadrate, pale; 
acrostichal and dorsocentral bristles conspicuous, scutellum with four white 
bristles; hypopygium terminal. 
Front broad above, narrow and sub-parallel below, cinereous; ocelli small, 
ocellar bristles small; occiput lightly pollinose, its cilia white and conspicuous; 
antennae small, black, the basal joint blackish, arista almost terminal, short, 
although four times the length of the antenna, microscopically pubescent. 
Eyes completely contiguous on the face, deeply but narrowly excised at the 
antennae, facets nearly uniform, those below larger. Palpi of male yellowish, 
one-half longer than broad, with three long terminal white hairs, in the female 
the palpi are dusky but with a white sheen. Proboscis black, no longer than 
the palpi, projecting somewhat forward. 
Thorax cinereous pollinose, humeri round, not quite as broad as the inter- 
humeral space, the furrow not deep except behind; all the thoracic bristles 
white, the acrostichal and dorsocentral rows well developed, the lateral bristles 
comparatively short, about a dozen in front of the wings: scutellum with two 
long and two short white bristles; no pleural bristles. Abdomen sub-shining 
olivaceous black, with sparse stubby whitish hairs, the lateral margins of the 
intermediate segments with the round black pits characteristic of Coloboneura, 
Parathalassius, ete. Hypopygium closed, terminal, elongate. Coxae shining, 
