THE THORAX. 107 



PI. XVI. f. 29), or several (Hippobosca, PL XVI. f. 29), teeth 

 (unguic. dentati), and at others, the under-edge is toothed like a saw 

 (unguic. serrati, or denticulate, Calaihus, Cistela, &c. PI. XVI. f. 30). 



Between these two hooks of the terminal joint, we perceive in some 

 insects a second smaller cla\v,called the SPURIOUS CLAW (pseudonychiaj, 

 but by Nitzsch empodium. Among the beetles, we find this structure 

 in Lucanns (PL XVI. f. 31). This claw perfectly agrees with the 

 larger one in its conformation, and consists, therefore similarly to this, 

 of a stalk-like basal-joint, at the end of which there are two little 

 hooks. In the Hymenoptera, Diptera, and some families of other 

 orders, we find instead of them, soft, gently convex, oblong, mem- 

 branous cushions, the SOLES (plantuce) or CLIMBING CUSHIONS (arolia, 

 Nitzsch, PL XVI. f. 32). These attach like sucking-cups, and there- 

 fore the insects provided with them (for example the Diptera) can run 

 lightly and securely upon vacillating objects. We seldom observe 

 spurious claws and cushions together (Laphria, PL XVI. f. 33) ; still, 

 more seldom, are both wanting as well as the larger claws (Xenos, 

 PL XVI. f. 34). 



The underside of the foot, or SOLE (planta) has, when very narrow, 

 nothing to distinguish it. But if the foot is depressed, the sole has a 

 peculiar clothing, which has been called FOOT-CUSHION (ptdvillus). It 

 consists very generally of short and stiff hair (Lamia, PL XVI. f. 35), 

 more rarely of radiating plumes ( Zabrus, PL XVI. f. 36), occasionally of 

 true fleshy cushions (Xenos, PL XVI. f. 34). Some genera ( Timarcha) 

 display minute cup-shaped hollows in the sole, which is then called 

 SPONGY (pi. spongiosa, PL XVI. f. 37). In the majority of the first 

 adduced instances, the margin also is covered with short hair. 



