178 INTERNAL ANATOMY OF INSECTS. 
certain and satisfactory information ;—the muscles of the 
legs having been described by Lyonnet and Cuvier, and 
those of the wings most particularly by Chabrier. In 
caterpillars, the muscles are situated in the interior of 
the articulations that form the legs: they consist of seve- 
ral bundles appropriated to each, which have their at- 
tachment in the parietes of the preceding joint, near the 
margin, and are inserted in the margin of that they 
move*. Lyonnet counted twenty-one muscles in the leg 
of the caterpillar of the Cossus; but eight of these were 
appropriated to the claw, or rather formed a pair of se- 
mipenniform muscles, having their insertion at the inner 
angle of its base’. In perfect insects, according to Cu- 
vier, each joint of the legs is furnished with a pair of 
antagonist muscles—a flexor and extensor, the former 
being the dower, and the latter the wpper muscle; and this 
pair has its insertion in the joint it moves, and its attach- 
ment usually in the preceding one: but those of the 
coxee—which are rofators, causing it to turn backwards 
or forwards—and the extensor of the thigh, have their at- 
tachment in the parietes of the trunk, and to the endo- 
sternum; one of the rotators of the anterior coxa, and the 
extensor of the anterior thigh to the antefurca; of the 
intermediate pairs to the medzfurca, and of the posterior 
to the postfurca*. Every joint of the farsus has also its 
flexor and extensor. In Dyéiscus L., Carabus L., &c., 
whose posterior coxz are immoveable, the thigh includes 
two pair of antagonist muscles¢. In extracting the pos- 
terior leg of Necrophorus Vespilio I observed more than 
@ Cuv. Anat. Comp. i. 436. Prare XXI. Fic. 6. 
> Ibid. a, 6. Lyonnet Anat. 37. © Cuv. ubi supr. 458—. 
Vor. UE. p. 369, 379, 388. * Cuv. Ibid. 459. 
