AMKKICAX DIFTKKA. 81 



THE DIPTICKOIK <ii:\KllA TA< II YTREC lll$« 

 AXD WAl'ELI.OC'KRlS. 



BY J.,M. ALDRICH. 



This grou]) of the Dolic^hopodiche coutaiiicd, at the time of Loew's 

 nionogra])h, one genus and three species. Since then Loew published 

 another species in his seventh Century, and Osten Sacken one in 

 " Western Diptera." Mik has established a new genus for a part 

 of the old one, and three now species are described in the pre:-ent 

 paper. 



These two genera form a well-defined group, with the following 

 characters : First antennal joint hairy above, arista dorsal, face 

 long, narrow, wider below and rounded at the tip, reaching as low 

 as the inferior border of the eye ; wings narrow, in the male espe- 

 pecially ; hypopygium of the male entirely disengaged, directed for- 

 ward under the venter, reaching nearly to the coxte ; hind metatarsi 

 without bristles above. 



The genera are separated by the following chai-acters : 



Male antemipe normal, like those of the female; fourth longitudinal vein ending 

 just before the extreme apex, at a considerable distance from the tip of the 

 third Tacliytrechiis. 



Male antennae with the second joint rudimentary and tlie arista elongated and 

 ending in a lamella ; fourth vein ending considerably before the apex, very 

 close to the tip of the third IVIacolloecrus. 



TachytrecliiiN Loew. 



KtaniiiiiM isis 1831, p. 261, Loew, Neue Beitraege. v, 1857; Hon. Dolicho- 

 podidie. p. 109. 



MALES. 



1. Wing of male with a spot at the tip 2. 



Wing of male without spot ani>;ii<<»tii>i'iiiii*$ Loew. 



2. The spot wholly black flori<l(>ii<<$is n. sp. 



The sjjot black in front, snow-white behind vorax Loew. 



FEMALES. 



Posterior femora yellow at the extreme ti]) only vorax. 



Posterior femora about a third of the length yellow florideilNiM. 



(The female of aiMpistipennis is not known.) 



TRANS. .\M. E.VT. SOC. XXiri. (11) M.VRCH, 1896. 



