Pupae

Abstract

The pupa is enclosed in the sclerotized integument of the third-instar larva, the puparium. The puparia are typically as in Fig. 4.1, with paired eclosion plates penetrated by the pupal respiratory horns. An example of a modified puparium is that of Megaselia fuscinervis, which is always located in the same position in the shell of its snail host (3.5.2) (Fig. 4.2). The paired eclosion plates are evidently fused together and also fused to the anterior segments, the whole being heavily sclerotized. The rest of the puparium, protected by the host’s shell, is only weakly sclerotized (Fig. 4.2). These modifications of the typical Megaselia state would seem to be a clear case of adaptations relating to the habit of pupariating in the host’s shell, reminiscent of the distorted puparia of the snail-parasitizing Sciomyzidae (e.g. Knutson, 1970; Barnes, 1990c). Other variations are considered below.

The pupa ‘is a unique invention of insects, and its intercalation in the life history has made possible the extreme divergence between the young and the adult’ (Bates, 1950)