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- 
buni 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 beyend 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 
