Dec., 1906.] 
Two New Species oj Diptera. 
29 
TWO NEW SPECIES OF DIPTERA BELONGING TO ASILINAE. 
James S. Hine. 
Up to the present time only a single species has been placed 
under each of the genera Machimus and Stilpnogaster. It is 
possible that others properly belonging here have been described 
under the genus Asilus where all the old authors placed nearly 
all their species of the subfamily. This latter genus has not 
been revised for North America, but all descriptions are accessi¬ 
ble, and the two species considered here appear to be distinct 
from others previously recognized, so are taken to be new. One 
species belongs to each genus mentioned. 
Machimus griseus n. sp. Male and female brownish gray 
with reddish legs and narrow white annulations at the apexes 
of the abdominal segments. Wings hyaline with well defined 
dark markings at the apex and posterior border. 
Front and face of usual width, gibbosity of the face prom¬ 
inent extending two-thirds of the distance from the oral margin 
to the antennae; mystax with black bristles above and white 
ones below; antennae black, rather long, third segment with its 
style decidedly longer than the other two segments combined, 
style equal in length to the other part of the segment; beard 
white. Thorax dark in ground color but clothed with gray 
pollen which is denser in some places than in others, thus giving 
the part a variegated appearance; a wide middorsal black stripe 
divided anteriorly by a narrow grayish interval; scutellum with 
two black bristles at the apex; legs red with numerous black 
bristles, coxae black, all the femora darkened before, except 
just before the apex of each; wing clear hyaline with dark mark¬ 
ings as follows: marginal, submarginal and first posterior cells, 
each with a stripe which reaches the apex of its respective cell; 
other posterior, discal and anal cells each with an angular spot 
not contiguous with the margin of the wing; halteres very pale 
in color. Abdomen of the same general color as the thorax, with 
a light colored annulation preceded by a row of nearly white 
bristles at the apex of each segment. Eighth segment of the male 
distinctly produced below, but not appendaged as in some of the 
European species of the genus; male genitalia reddish in color, 
oviduct shining black. Length of male and female, 17-20 mm. 
Habitat: Several specimens from Southwestern Colorado. 
The female is larger than the male in the specimens before 
me. The water clear wings with the well defined markings as 
described are sufficient to distinguish the species from its near 
relatives. 
Stilpnogaster auriannulatus n. sp. General color shining blue- 
black with uniform pale brown wings and black and yellow legs. 
