Dec, 1906.] Two New Species of 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. 



