Fig. 33.—Profile of Male and Female Cockroach. × 4.
The externally visible appendages of the abdomen are the cerci and the styles of the male Cockroach. The cerci are found in both sexes; they are composed of sixteen rings each, and project beneath the edge of the tenth tergum. They are capable of erection by special muscles, and are supplied by large nerves.[81] The sub-anal styles are peculiar in their insertion, being carried upon the sternum of their segment (the ninth).
The abdominal segments are never furnished with functional legs in adult Insects, but representatives of the lost appendages are often met with in larvæ. According to Bütschli,[82] all the abdominal segments are provided with appendages in the embryo of the Bee, though they disappear completely before hatching. Some Hymenopterous larvæ have as many as eight pairs of abdominal appendages, Lepidopterous larvæ at most five (3–6; 10).[83]
CHAPTER V.
The Muscles; the Fat-Body and Cœlom.
SPECIAL REFERENCES.