296 DIPTERA FROM SOUTHWESTERN UNITED STATES 



7. Frons in both sexes narrow, in the female without cruciate frontal bristles 

 and the lower supraorbital bristle not directed forward, or very weak 

 and but little proximad of anterior ocellus; face and frons buccate, 

 the parafacials in profile as wide or wider than the third antennal joint, 

 abdomen in male cylindrical; the hypopygium very small. 



Hammoinyia R.-D. 

 Frons in male usually narrow, in female nearly or quite one-third as wide 

 as head, the lower supraorbital usually very strong and situated nearly 

 midway between anterior ocellus and anterior margin of frons; face and 

 frons rarely buccate, the parafacials in profile usually less than the 

 width of the third antennal joint; abdomen sometimes sulx-ylindrical 



Hylemyia R.-D. 



The distinction between the last two genera is not very clear in 

 the males, some of the species of Hylemyia resembling Hammo- 

 mijia very closely, but the females are readily separated and with 

 a little care the males may also be distinguished. 



HYDROPHORIA R.-D. 



The members of this genus which I have seen possess the fol- 

 lowing characters: ej^es bare, narrowly separated in male, widely 

 separated in female, the lower supraorbital bristle in female 

 directed forward; arista long haired; prealar bristle present; 

 abdomen in male subc^dindrical; fifth sternite with two long 

 processes; lower calypter much larger than upper. 



Hydrophoria subpellueida sp. n. 



Male and female. — Black, slightl}^ shining, covered with dense whitish 

 gray pruinescence. Head black, orbits and cheeks silvery pruinose; frontal 

 triangle reddish brown; antennae black, second joint shghtly reddish at apex; 

 palpi blackish brown. Thorax when viewed from in front with four subcon- 

 tiguous black vittae anteriorly, when viewed from behind with five black 

 vittae, the areas between the vittae pale gray and when seen from in front 

 assuming a black appearance, reversing the black and gray arrangement 

 Abdomen yellow on basal half, covered with dense whitish pruinescence, and 

 with a broad, central black vitta. I^egs pitchy colored, the bases of tibiae 

 pale, yellowish. Wings hyaline. Calyptra white. Halteres yellow. 



Male. — Eyes separated by about the width of anterior ocellus; parafacials 

 protruded in profile about as far as two-thirds the width of third antennal 

 joint; arista very long plumose both above and below; cheek about one-eighth 

 as high as eye, marginal bristles in a single row. Thorax with two to three 

 pairs of presutural acrostichals; prealar bristle about half as long as the bristle 

 behind it; h3'popygium bare. Abdomen short, subcorneal; processes of fifth 

 sternite short, rounded apically, with rather dense, short black hairs, and a few' 

 long apical bristles. Fore tibia with one antero-dorsal and one posterior 



