THE CRANE-FLIES OF NEW YORK PART II 745 



in many Eriopterini and some Limnobiini (Dicranoptycha) . It is mada 

 up of the composite head capsule, three thoracic segments, and nine 

 evident abdominal segments. In some species all the abdominal segments 

 are subdivided, respectively, into a narrow basal and a usually broader 

 posterior ring, or annulus; in other species only the basal segments are 

 so subdivided. The integument is usually covered with a dense appressed 

 pubescence and often bears setae, or pencils of hairs, or, in some Cylin- 

 drotominae, spinous projections. 



Respiration is characteristically metapneustic ; in the Rhyphidae it is 

 amphipneustic, in Antocha apneustic. The typical metapneustic forms 

 often show vestigial lateral spiracles, but these are not functional in any 

 species known to the writer and the peripneustic type of larva is still 

 unknown in this group of Diptera. The spiracles are placed at the ends 

 of the long breathing tubes in the Tanyderidae and the Ptychopteridae. 

 In the Tanyderidae, the Tipulidae, and the Rhyphidae the disk is sur- 

 rounded by a varying number of lobes which are rarely indistinct, these 

 ranging in number from two to eight. Anal gills are found in -repre- 

 sentatives of almost all the major groups of crane-flies, and their loss is 

 a result of habitat and non-usage. In wood-inhabiting species the gills 

 are often modified into blunt lobes, having the evident function of pro- 

 pulsion by shoving. 



Body form 



As already stated, in the majority of crane-fly larvae the body is terete 

 or approximately so, but in some species it is decidedly depressed with 

 the ventral surface flattened. Such forms are Dactylolabis, some Cylin- 

 drotominae, and some Tipulinae. The integument is produced into 

 elongate spines and blades in almost all species of Cylindrotominae, similar 

 conditions being suggested in a few tipulines. A definite arrangement of 

 setae (chaetotaxy) obtains. The basal abdominal ring is provided with 

 a transverse creeping- welt in the Limnobiini and in some Hexatomini 

 and Pediciini, as well as in a few other forms. In some genera, 

 as Epiphragma, this welt is practically naked; in others it is covered with 

 a microscopic scurfiness; while in still others (Dicranota) it is separated 

 into distinct paired prolegs, which are armed with circlets of chitinized 

 hooks that lessen in size from the tips basally. The welts are both dorsal 

 and ventral in position in many Limnobiini and in some Pediciini (Rhaphi- 



