April, 1911.] New Species of Diptera of the Genus Erax. 
Female abdomen with each segment white pollinose at sides 
and apex, otherwise black above, ovipositor black, scarcely five 
millimeters in length, equivalent to the last three abdominal 
segments. 
Twenty specimens received from F. Grinnell, Jr., and taken in 
Los Angeles County, California. A very distinct species on 
account of the male hypopygium which appears as if inflated and 
is nearly twice as wide as the seventh abdominal segment. 
Erax nemoralis n. sp. A dark colored species with yellowish 
mystax and fumose wings. Femora, tarsi and apices of the 
tibiae black, bases of tibiae reddish-brown. Length, male about 
25 millimeters, female to the tip of the ovipositer, 2-1 to 27 
millimeters. 
Face and front covered with yellowish dust, mystax and beard 
pale yellow, occipito-orbital and ocellar bristles black, as are 
most all of the hairs and bristles of the front, palpi black, fur- 
nished with many black hairs which often are intermixed with 
pale yellow ones. Prothorax mostly clothed with pale hairs, 
remainder of thorax with many black hairs and bristles, but 
these often arc reduced by the presence of greater or less numbers 
of pale ones; middorsal stripe dark and well marked, abbreviated 
behind and divided anteriorly, on either side the markings are in 
the form of ill-defined spots caused by the difference in intensity 
of the rust-colored dust which gives the thorax its peculiar color; 
legs black except the bases of the tibiae which are reddish-brown, 
clothed with black bristles and pale hairs of different lengths, the 
shorter ones recumbent, some of the segments inwardly, more 
especially the metatarsi and front tibia, clothed with golden 
recumbent pile. 
In the male abdominal segments one, two and base of three 
dark, largely clothed with black hair, apex of three and all of four, 
with the exception of a small black triangle on each anteriorly, 
white with long white hair parted at the middle and directed out- 
ward, five and six silver white with very short hair, remainder of 
the abdomen black, with black hair, however, in some specimens 
part of seven is whitish and there may be a few pale hairs on the 
hypopygium. 
In the female the segments of the abdomen are gray on the 
sides and hind margin, otherwise black above but the latter color 
is not well defined, especially if viewed with a lense; ovipositor 
about six millimeters in length, equivalent to the last four 
abdominal segments. 
Several specimens of both sexes procured in a brushy woodland 
at New Roads, Louisiana, July 15, 1905. The specimens were 
captured while resting near or on the ground. It is a predaceous 
insect of possible value on account of its size. 
