276 DIFTERA FROM SOUTHWESTERN UNITED STATES 



Trichopticus maculiTentris .s]3. n. 



Female — Black, slightly shining, with dense yellowish brown pruinescence. 

 Head entirely black, the interfrontalia velvety black when seen from behind. 

 Thorax with a blackish vitta on each side between acrostichals and dorso- 

 centrals on anterior half of dorsum. Abdomen with a pair of rounded, widely 

 separated black spots on dorsum of segments two and three, and a much less 

 distinct dorso-central stripe or series of spots on all segments. Legs black. 

 Wings clear. CaljTJtra and halteres orange yellow. 



Eyes bare, separated by over one-third the width of head; ocellar triangle 

 not carried to middle of frons; orbits one fourth as wide as interfrontalia, each 

 with four bristles, the lower one strongest, the one above it directed forward, 

 no hairs on orbits; cruciate bristles moderately strong; antennae stout, shorter ' 

 than face, third joint nearly three times as long as second; arista with distinct 

 pubescence; parafacials not visible in profile; cheek about one-eighth as high 

 as eye. Presutural acrostichals strong, three pairs, with interspersed hairs; 

 post-sutural dorso-centrals three, the anterior one weak, probably sometimes 

 duplicated; sternopleurals 1: 1. Fore tibia unarmed at middle; mid femur 

 with one strong bristle at middle on anterior side; mid tibia with one posterior 

 bristle; hind femur with three to four short bristles on apical third of antero- 

 ventral surface; hind tibia with two to three weak, short bristles on antero- 

 ventral surface; preapical dorsal bristle rather far from apex. Third and 

 fourth veins slightly convergent at apices; outer cross-vein slightly curved; 

 lower calypter very little larger than the upper. Length, 3.75 mm. 



Type.— 9 ; Troy, Idaho, May 31, 1908, [A. N. S. No. 6199]. 



This species differs from all others known to me in having no 

 strong bristles on postero-dorsal surface of hind tibia, and in hav- 

 ing the dorsum of the abdomen with paired spots. It bears a 

 strong resemblance to species of the genus Hydrotaea in thoracic 

 chaetotaxy, but no species of the Hydrotaeinae has the bristles 

 on apex of hind coxae above, as in this species. 



POGONOMYIA Pokorny 



Recently a revision of this genus by Dr. J. M. Aldrich appeared 

 in Entomological News.^ The definition of the genus given in 



3 1918, p. 179. 



that paper is, though vague, as good as any previously pubhshed, 

 but does not, mention the characters cited in the key to genera 

 given on a preceding page of the present paper. A summary of 

 the generic characters is as follows: Eyes bare, narrowly separated 

 in the male, widely separated in the female, orbits bristled on 

 their entire length in both sexes, loicer supraorbital in female 

 directed forward; parafacials broad in profile, sometimes as broad as 



