AMERICAN DIPTERA. 



279 



Small species (3.0 mm.) 15. minor n. sp. 



Larger species (4.5 mm.) 16. atlanticus Hough. 



Abdomen shining, with extreme bases of segments more or less 

 opake-black ; post-femora much thickened and somewhat 



discolored with brown (Fig. 121) 24. femoratus n. sp. 



Abdomen shining, except first segment, and lateral margins cinere- 

 ous ; femora slender, not discolored 33. houg'hii Kert. 



20. Hypopygium cleft 21. 



Hypopygium not cleft 24. 



21. Abdomen opake, or subopake, more or less variegated with 



gray 22. 



Abdomen polished, at most gray only at base and ventral mar- 

 gins 23. 



22. Abdomen opake, brown and gray fasciated ; tibiae and tarsi yellow. 



14. aequus n. sp. 

 Abdomen subopake, evenly brownish tinged, only faintly marked 

 with gray. 



New Mexico species 12. fuscitarsus Adams. 



New York species 11. discolor Banks, n. sp. 



23. Antennas yellow, long acuminate ; knobs of halteres black ; wings 



hyaline, with only apical portion of stigma colored. 



35. tarsalis Banks, n. sp. 

 Antennas black, short, acute ; halteres yellow ; wings brownish. 



23. vitlmis n. sp. 



24. Abdomen subopake, with more or less grayish tinge on dorsum. .25. 

 Abdomen polished, only grayish at base and laterally. 



35. tarsalis Banks, n. sp. 



25. Hypopygium small, shorter than fifth segment; abdomen sub- 



cylindrical 3. affinis n. sp. 



Hypopygium large, longer than fifth, very broad ; abdomen ovate, 

 distinctly broadest at third and fourth (Fig. 72). 



4. coiifratermis Banks, n. sp. 



26. Legs and antennas entirely yellow 27. 



Legs yellow, with only a small, well defined, black, sub-basal 



femoral spot (Fig. 127) ; abdomen entirely shining black. 



38. atraiiionteiisis Banks, n. sp. 

 Legs in part black 29. 



27. Abdomen opake, brownish, more or less cinereous. Mexican 



species 40. flavicomis Will. 



Abdomen shining, more or less yellow laterally 28. 



28. Antennas acutely pointed. Mexican species. 



j««f 39 - xanthopodus Will. 

 Antennas long, white acuminate 4& flavomaculatns Hough. 



29. Tibias mostly yellow ; first and lateral margins of segments 2-4 



iensely cinereous ; hypopygium very large and symmetrical. 



36. albofasciatus Hough. 



TRANS. AM. ENT. SOC, XXXVI. DECEMBER, 1910. 



