976 CHARLES PAUL ALEXANDER 



developed according to the habitat. The head capsule is remarkably 

 uniform thruout the group, being broad, compact, and massive, with the 

 posterior incisions shallow and the prefrontal sclerite very large and 

 usually distinct. The labrum is usually conspicuous, transverse, with 

 fringes of hairs. The mentum has from seven to nine teeth along the 

 anterior margin, and is deeply split behind but not completely divided. 

 The hypopharynx consists of a narrow, flattened plate, with the basal 

 lateral angles produced into strong arms and the anterior margin having 

 usually five teeth, the teeth being rarely more numerous and in some 

 cases obsolete. The antennae are cylindrical, and are stoutest in the 

 wood-inhabiting species; in many species of Tipula and Prionocera they 

 are long and slender, the length being about four times the diameter; 

 the apical papilla, in some cases obsolete, is usually very small and is 

 flattened. The mandibles are not large in proportion to the size of 

 the capsule; they have few teeth, in some species only a dorsal and a 

 ventral tooth in addition to the apical point; the prosthecal appendage 

 is variously developed. The maxillae are simple and generalized in 

 structure. 



The pupae are fairly uniform in structure thruout the subfamily. The 

 tips of the sheaths of the maxillary palpi are strongly curved, or, in the 

 majority of species, actually recurved. The pronotal breathing horns are 

 variously formed, but in practically all species they are short, cylindrical, 

 and with the tips but little expanded. In some genera (Longurio, 

 Prionocera, and Tipulodina) the breathing horns are greatly elongated, 

 and, in some cases at least, are slightly unequal in length, the longer 

 measuring nearly half the length of the body. In some genera, such 

 as Prionocera and Holorusia, the horns are split at their tips into two 

 divergent flaps. The only short, clavate horns in the subfamily are 

 those of the genus Tanyptera. The mesonotum is often provided with 

 four or six variously developed tubercles. The abdominal segments are 

 almost always armed with transverse posterior rows of spines, these 

 ranging in number from about four to twenty. 



The large size of the larvae and the pupae will, as a rule, easily separate 

 this subfamily from almost all members of the Limnobiinae. The few 

 large members of the latter group are readily separated by the characters 

 outlined above. 



