Difference of opinion as to the nature of the abdominal appendages pre vails.

The larvae have the three pairs of legs well developed, and the hinder abdominal segments swollen.

The fourth abdominal segment is often very large, and forms the greater part of the hind-body; this segment is markedly constricted at its basal (forward) end, where it is embraced by the small third segment.

The male opening is on the ninth abdominal segment, to which belong the processes that form the claspers or genital armature.

n, First Abdominal Segment.