466 PROCEEDINGS OF THE ACADEMY OF [Sept., 



variation in the number of antennal segments is found in other 

 genera of crane-flies (Ctedonia, 15 to 24 segments; Cerozodia, 32 to 

 39 segments; Tanyderus, 17 to 25 segments), and consequently too 

 much significance should not be placed upon this variable character 

 in these groups. 



The genus Puchyrrhina was described at a much later date, and 

 consequently the numerous species known throughout the world 

 under this name must be referred to Nephrotoma. The change in 

 the American species affects all of the described forms with the excep- 

 tion of collaris Say, polymera Loew, nohilis Loew, unimaculata Loew, 

 calif ornica Doane, trinidadensis Alexander and macrostema Alexander, 

 which should be referred to the genus Tipula as discussed below. 



The discover}^ of an ultimate character to separate the species of 

 Nephrotoma from those of Tipida is still largely a desideratum. 

 There are a number of characters which, if used in combination, 

 should serve to separate the species of the two genera. The majority 

 of the characters cited below should hold in all cases. Venationally 

 these characters are as follows: 



(1) The very short, usually almost transverse, radial sector of 

 Nephrotoma, which in many species is transverse and simulates a 

 cross-vein; in other species longer and more ol)lique, reaching its 

 maximum length apparently in species such as vittula Loew. 



(2) The sessile cell Mi in Nephrotoma, this being rarely short- 

 petiolate. This character has long been known, having been clearly 

 stated by Schiner (1864). Species of Tipula with the cell sessile 

 are unknown. 



(3) The basal deflection of Cui and the cross-vein m-cu at or 

 before the fork of M. This character, described for the first time by 

 Czizek- and independently by Brunetti,^ is the nearest approach 

 to absolute of any that we have, but even this is approached by 

 some species of Tipula (the jnarmoraice group, fragilis Loew, ignohilis 

 Loew, et al.). 



The male hypopygium of Nephrotoma shows the ninth pleurite 

 never completely fused with the ninth sternite, the more generalized 

 condition occurring in such species as incurva Loew, where the 

 pleurite is almost entirely separated from the sternite, through 

 lugens Loew, where the pleural suture is straight and not curved 

 dorsally toward the tip, to the more specialized condition with the 



2 Tipulidse Moravicae; Zeitschrift des Mahrischen Landesmuseums, vol. 11, 

 p. .50, 1911. 



•■' Fauna of British India, Diptera Nematocera, p. 340, 1912. 



