The Morphology of the Head-Capsule of Some Coleopterous Larvae

Abstract

A comparative study of the external morphology of 46 species of the more common coleopterous larvae. The antennae and ocelli exhibit wide variation. From the fronto-dorsal aspect, the generalized structure of the head is shown, with which may be compared the modifications which occur and which lead to the disappearance of all the sutures separating the different areas found in this region. From the postero-ventral aspect, the heads are divided into two distinct groups, those that possess a gular area and those that do not. Here again, the specialization is compared with the generalized condition. Where a gula occurs, its development is first traced through the series, and then its gradual suppression, due to specialization, is illustrated. The disappearance of sutures causes the head-capsule to become very compact and heavily sclerotized, and this condition is found to be more general and complete in the campodeiform type of larvae.