Replacement of a Cuticular Apophysis in Larval Sarcopha Bullata (Diptera, Insecta) During Moulting

In arthropods, growth of hard body parts is achieved during periodic moults. At such times, a new cuticle is formed and, after some reabsorption, the old is discarded. For much of the exoskeleton, which is bounded externally by the epidermis, the sequence of events in moulting has been well documented (Neville 1975, Hackman 1971, Hepburn 1976, Hepburn 1985). Replacement of some cuticular structures would appear to be more complex. Apophyses are solid internal projections of cuticle, frequently forming muscle attachments, which arise from either the external body wall or the linings of the foreor hind-gut (Neville 1975, Hepburn 1976). Embryological formation of these structures produces solid pieces of cuticle surrounded by epidermal tissue. It would seem that following the first and subsequent ecdyses, secretion of new cuticle from the surrounding epidermis would produce an invaginated fold of cuticle rather than the single structure of a typical apophysis. The manner in which apophyses can be conserved during moulting is described in this paper.