Surface specializations of the hindgut cuticle of lepidopterous larvae

Abstract

The cuticular intima lining the pyloric region of the hindgut of lepidopterous larvae bears numerous spines, comprising four distinct types, which are arranged in regular discrete patterns. On the basis of location, form, and other criteria three of the four types of spines have clearly attributable roles in alimentary function. One of these roles is the shredding of the peritrophic membrane as it passes through the pylorus. Although the spines are arranged in a basic pattern characteristic of lepidopterous larvae, there is within this basic pattern considerable diversity among species.The intima of both the colon and anterior rectum, although devoid of spines, is pitted with numerous small depressions. The presence of these small depressions is probably indicative of the reabsorptive abilities of the underlying epithelium.