756 CHARLES PAUL ALEXANDER 



root; this is usually armed with from one to three setae. Various other 

 setae usually occur on the mesonotum. 



The leg sheaths lie along the ventral side of the pupa. There is, in the 

 various groups, a considerable difference in the length of the sheaths, 

 their position, and the relative arrangement of the ends of the tarsal 

 segments. In the Bittacomorphinae, the fore legs overlie the middle 

 legs. In the Rhyphidae the fore legs overlie the middle pair, which, 

 in turn, overlie the hind legs. In the Ptychopterinae and in the Tipulidae, 

 all three pairs of sheaths lie parallel along the midventral area, those 

 of the hind legs being outermost along the wing sheaths, and those of 

 the fore legs being on the inside and contiguous. In Gnophomyia the 

 leg sheaths are very short, extending but little beyond the wing tips and 

 reaching only the end of the second abdominal segment. In other crane- 

 flies they are longer, in some species reaching the end of the fifth abdominal 

 segment. Very often the tips of the tarsi are on a level. In the Limno- 

 biini the hind tarsi are usually a little shorter, and the fore tarsi are a little 

 longer, so that the ends of the sheaths form a blunt V. In the Eriopterini 

 the middle legs are usually (except in Gnophomyia) much shorter than 

 the other legs; in Helobia, moreover, the hind legs are conspicuously 

 longer than the fore legs, so that all three sets end at different levels. 

 A somewhat similar and parallel development is found in the tipuline 

 forms. 



The wing sheaths are moderately broad, usually ending opposite or 

 a little beyond the apex of the second abdominal segment. The venation 

 of the various species often shows clearly and with little distortion on 

 the wing pad, and in such cases it is of very great help in locating certain 

 genera. Species with a heavy pattern in the adult wings, such as those 

 of the genera Discobola and Epiphragma, show this pattern on the wing 

 pad in the older pupae, and this helps to confirm their identity. 



The abdomen 



The abdomen consists of apparently nine segments, the last two being 

 closely approximated or fused to form the cauda. The segments are 

 usually plainly divided into a broad dorsal (tergal) and ventral (sternal) 

 region, and a much narrower and more restricted lateral (pleural) area. 

 The segments beyond the first are variously subdivided into rings, or 

 annuli, by false constrictions, there being usually one, but in some cases 



