239 



HABITS OF LARVAE 



The larvae are found in damp situations, frequently in water, and 

 feed upon decaying vegetation and algae. 



HABITS OF IMAGINES 



The imagines are usually found near streams or other bodies of 

 water. They are frequently taken upon flowers. Several species of 

 Ptychoptera are common in Europe, but they are much less so in 

 North America, occurring but rarely in Illinois. 



Key to Genera 



LARVAE 



1. Body with transverse series of wart-like elevations surmounted by 

 hairs ; ventral cephalic sclerite conspicuously narrowed posteriorly 



Bittacomorpha. 



— Body without transverse series of wart-like elevations, but armed 

 with hairs in transverse series; ventral cephalic sclerite slightly 

 narrowed posteriorly Ptychoptera. 



Bittacomorpha Westwood 



This genus is represented by many examples of clavipes, in all 

 stages, in the collection before me. This material was used by Mr. 

 Hart in drawing up his description of the larval and pupal stages in 

 the paper frequently mentioned herein. The superficial characters of 

 the larva and pupa are well illustrated by Figures 4 and 6, Plate XXX. 

 The following description should be regarded as supplementary to the 

 previously published one. 



Bittacomorpha clavipes Fabricius 



Tipula clavipes Fabricius, Mantissa Insectorum, Vol. 2, p. 323. (1787) 



Larva (PI. XXX, Fig. 4). — Length, including extended respira- 

 tory tube, 50-60 mm. Pale brownish, with the dorsal surface of head 

 marked with dark brown granulose elevations, and the transverse 

 series of warts on bodv darker than remainder of ground-color (PI. 

 XXXV, Fig. 5). 



Ventral surface of head as in Figure 8, Plate XXXV, the central 

 sclerite very much narrowed posteriorly, the anterior margin con- 

 cave; maxillary palpi and antennae longer than in Ptychoptera; 

 labrum seen from above about half as long as broad ; mandibles as in 



