192 



FAMILY CHARACTERS 



Larva. — Head heavily chitinized, retractile within prothorax; 

 posterior portion deeply cleft longitudinally, one incision on each side 

 of dorsum extending to, or almost to, middle, and one in center of 

 venter extending beyond middle. Antennae elongate, consisting of an 

 elevated base, an elongate joint — in Tipula at least four times, in 

 Xiphura not more than twice, as long as broad — and a very short 

 apical process. Front and clypeus fused, the former with a distinct 

 plate on each side, the anterior margin of which is armed with a 

 few bristles and many hairs; labrum fringed with hairs anteriorly; 

 epipharynx with a number of spines or short processes. Maxillae well 

 developed, fringed on the inner and anterior margins with hairs, and 

 sometimes spinose ; palpi small. Mandibles stout, the apex rounded and 

 with 2 teeth more or less equal in size, lower margin with 2 or more 

 teeth, inner upper margin with a fringe of hairs near middle. Labial 

 plate (submentum) in the form of a flat plate, its outline medianly 

 produced into an acute point anteriorly, the margin more or less dis- 

 tinctly dentate. Hypopharynx heavily chitinized, in the form of a 

 flat plate the anterior margin of which is usually dentate, and with 

 a posterior inverted-U-shaped chitinized piece which arches over the 

 oesophageal opening. Body cylindrical ; segments usually with dis- 

 tinct hairs which are situated on certain portions of each segment, 

 their arrangement being uniform throughout the family ; pseudopods 

 present or absent; segments always with transverse linear depressions, 

 most distinct on dorsum ; apical segment with 6 processes, rarely with- 

 out these being well developed ; ventral surface of apical segment in 

 aquatic and semiaquatic species with fringes of soft hairs on apical 

 processes and with slender protrusive blood-gills ; terrestrial forms 

 with the fringes of hairs much reduced or absent, and the slender 

 protrusive blood-gills usually absent, their function being performed 

 by an irregular protrusive membranous organ. 



Pupa. — The pupae differ from those of Limnol)iidac in minor 

 characters only,- the principal distinction between them and pupae of 

 the genus Lhnnohia and several other genera consisting in the form 

 of the thoracic respiratory organs, those of Tipulidae, exclusive of 

 Ctenophorinae, being long and slender, while those of the other family 

 are stout and resemble a chitinized flattened plate. Manv of the 

 Limnobiidae, however, have slender thoracic respiratory organs, and 

 other characters must l)e depended upon to distinguish them from 

 Tipulidae. A brief summarv of the characters of tip.ulid pupae is as 

 ii'llows: head without projecting chitinized armature; antennae 



