PECULIAR TRACHEAL DILATATIONS IN 

 BITTACOMORPHA CLAVIPES FABR. 1 



CHARLES THOMAS BRUES. 



BITTACOMORPHA is a member of a very aberrant group of 

 Tipulidae. In connection with two other genera it has been 

 separated from the Tipulidae and considered as a distinct 

 family. Of the genus Bittacomorpha only two species are 

 known, both from North America. The species upon which 

 these remarks are based is the commoner and more widely 

 distributed form. It occurs from the New England states 

 westward to the Pacific coast and has been taken as far south 

 as Florida by Osten Sacken. In the northern states it is 

 double brooded, and the imagines are seen during May and 

 September, although much more commonly in the spring. 

 The other species (Sackenii), which was described by Von 

 Roeder in iSgo, 2 is much more limited in its distribution and 

 is recorded only from Nevada. 



The common species (Fig. 3) is of the very slender form so 

 characteristic of the Tipulidae. Its appearance is remarkable, 

 however, on account of the peculiar black and white banding 

 and the great inflation of the metatarsi of all the legs. The 

 preparatory stages of a European species of the closely allied 

 genus PtycJioptcra have long been known, but it was only very 

 recently that the larva and pupa of Bittacomorpha clavipcs 

 were discovered and figured by Hart. 3 The larva, like that of 

 Ptychoptera, is aquatic, living among the submerged brushwood 

 and sticks, which it resembles in color and external appearance. 

 It is in this instar that we find the first peculiar modification 

 of the tracheal system. The larva is furnished with an elon- 



1 Contributions from the Zoological Laboratory of the University of Texas, under 

 the direction of Wm. M. Wheeler, A r o.j. 



2 IViener Ent. Zeitung. Heft 8, p. 230. 



8 Bull. Illinois State Lab. Nat. Hist. Vol. iv, p. 193. 



'55 



