662 EXTERNAL ANATOMY OF INSECTS. 



in Sphcx and Ammophila, but not in Pelopccus and Chlo- 

 rion, is fringed externally with long bristles. 



7. Composition. With regard to their composition, 

 both arms and legs generally consist of Jive pieces, which 

 Entomologists have denominated — the coxa or hip — the 

 trochanter — the femur or thigh — the tibia or shank — and 

 the tarsus or foot. Where the structure and use of the 

 fore-leg is different from that of the four hind-legs, I pro- 

 pose calling these pieces by names corresponding with 

 those which anatomists have appropriated to the arm in 

 the higher vertebrate animals : thus, as you will see in 

 the table, 1 call the whole fore-leg the brachium or arm ; 

 and the coxa becomes the clavicula or collar-bone ; the 

 trochanter, the scapula or shoulder-blade ; the femur, the 

 humerus or shoulder ; the tibia, the cubitus or arm ; the 

 tarsus, the manus or hand. But let me not lead you to 

 suppose that the pieces, either in the arms or legs of in- 

 sects, which are there named after certain others in verte- 

 brate animals, precisely correspond with them — by no 

 means — since that is a very doubtful point ; and some of 

 them, as the trochanter, clearly do not. Many gentlemen 

 skilled in anatomy, as I have before observed a , have 

 thought that what is regarded as the coxa in insects really 

 represents the femur: but there are considerable difficul- 

 ties in the way of this supposition, several of which I then 

 stated. I shall not however enter further into the sub- 

 ject, and take the above names ; since this application of 

 them is so general and so well understood, except with 



a See above p. 591. Some physiologists have been of opinion, 

 that in bm-ds, what is called the thigh should properly be denominated 

 the mm, and that this last is really the tarsus. Uliger, Terminohme, 

 184. § 185. n. 1246. to 



