46 CALIFORNIA ACADEMY OF SCIENCES [Proc. 4th Ser. 



Abdomen obscure yellow, the basal segments brighter; caudal margin of 

 the tergites narrowly ringed with paler; hypopygium reddish. Male 

 hypopygium very large and powerful. Ninth tergite very powerful, tumid, 

 the lateral angles produced caudad into elongate-triangular horns that are 

 slightly twisted, the extreme tips acute, bent slightly laterad and dorsad ; 

 the median notch is broadly U-shaped, on either side of the median line 

 with a small, chitinized, flattened projection, the apices obliquely truncated. 

 Ninth sterno-pleurite very restricted between the large ninth tergite and 

 eighth sternite, the pleurite almost complete. Outer pleural appendage 

 slender, clavate, pale, provided with long bristles. Gonapophyses project- 

 ing from the genital chamber as straight chitinized rods. Eighth sternite 

 with two brushes of short yellow hairs, one on either side of the median 

 line; lateral angles produced proximad into pale, complex arms that are 

 branched at their tips, the cephalic arm jutting backward underneath the 

 ninth sterno-pleurite, the tip provided with a brush of hairs, almost like 

 those on the caudal margin of the sternite. 



Habitat. — California. 



Holotype, S , Claremont (C. F. Baker), in the collection of 

 the author. 



Tipula megatergata is closely allied to T. tcrgata Doane and 

 T. sternata Doane, especially the latter, but differs in the details 

 of structure of the male hypopygium. 



