Larva, Pupa or Adult? The Female of Platerodrilus Case (Coleoptera: Lycidae)

Abstract

The anatomy and genitalia of a larviform female were studied for the first time in the family Lycidae. The structure of the exo- and endoskeleton of a Platerodrilus female was found to be not much different from that of its larva, with external genital appendages barely differentiated. The reproductive system was found to include an unpaired spermatheca, and paired oviducts and ovaries. The structure of the integument was found to also be peculiar, with two layers of cuticle differing in structure. On the other hand, the labrum and mandibles were found to be quite unlike the larval ones: the labrum was undivided and the mandibles fully metamorphosed. This odd combination of morphological characters may be interpreted in two ways. First, it may be hypothesized that this is a pupa. However, its genital appendages are simpler than those of “normal” Lycidae pupae; wings or their rudiments are completely absent; there are very few features of imaginal morphology in the external structure. Therefore, we propose another hypothesis—this is the stage preceding the pupa, which Hinton (1946) designates as ‘prepupa’.