Drilids-Drilidae

A few families of beetles, notably the Drilidae, Lampyridae, Cantharidae, and Lycidae, exhibit a peculiar sexual dimorphism; that is, the males and females have quite different appearances. Most females of these families are wingless and bear a much closer resemblance to the larvae than to the adult males.

This sexual dimorphism is extremely pronounced in the Drilidae. The female of Drilus flavescens, for example, differs in appearance from the male to such an extent that, at one time, the females were grouped in a species of their own, Cochleoctonus vorax. The males are smaller than their larviform mates. Males have another distinguishing characteristic: large comblike antennae.

Because of their peculiar structures, the males and females of Drilus fla-uescens have different life styles. The wingless females spend their time crawling on the ground. Only occasionally do they climb trees. Then they do it in order to attract males by emitting a special odor. The males, on the other hand, are usually seen flying around the foliage of trees.