128 NEW YORK STATE MUSEUM 



for the possesion of a rudimentary branch near the basal third of 

 subcosta. The third vein in this group extends well beyond the 

 apex before fusing with costa, except in Winnertzia. The very 

 slender, linear wings of Colpodia are unique in the family. The 

 antennae exhibit great diversity of structure, presenting, as do other 

 organs, types of extreme development. The stem of the flagellate 

 segments n some males has a length three times that of the basal 

 enlargement. The setae are extremely long and in some forms 

 present an arrangement not far removed from the characteristic 

 crenulate whorls found in Campy lomyza. The circumfili are more 

 aberrant than in any tribe aside from the Itonididinariae. These 

 organs are frequently set at a considerable distance from the face of 

 the segment, in this respect approaching Schizomyia, and display a 

 marked tendency toward distal prolongation. This is particularly 

 well marked in Winnertzia with its minute horseshoelike structures, 

 nails and all, on opposite faces of the segments. The claws may be 

 simple or unidentate and in some species are distinct y swollen 

 subapically. The male genitalia present most striking diversities. 

 The terminal clasp segment may be obese as in some species of 

 Porricondyla, greatly dilated subapically as in P. ham at a, or very 

 greatly produced and slender as in Didactylomyia. The ovipositor 

 in the female is frequently short, with the terminal lobes biarticulate, 

 or the ovipositor may be extensile and with the biarticulate lobes 

 subapical and dorsal as in Winnertzia. 



Little is known of the life history of our American forms and there 

 is such great diversity between the two sexes that the present classi- 

 fication must be regarded as largely preliminary. Most of the 

 species presumably live in dead or decaying vegetable matter. 



Key to genera 



a Crossvein not parallel with costa, forming a well-marked angle therewith 

 b Four long veins, the fifth simple, the sixth free 



c Fifth vein arising from the third near the crossvein, a supernumerary vein 



at the basal third of subcosta Diallactes Kieff . 



cc Fifth vein arising from the base of the wing, no supernumerary'- vein at 

 the basal third of subcosta 

 d Fifth vein well developed; circumfili modified to form horseshoelike 

 appendages on opposite faces of the segment 



Winnertzia Rond. (Syn. Winnertziola Kieff.) 

 dd Fifth vein rudimentary, obsolete basally and apically (Australian) 



Gonioclema Skuse ' 

 bb Three long veins, the sixth a branch of the fifth or wanting 



c Wings not very long and narrow, the crossvein at an oblique angle to costa 



1 Location provisional. 



