126 GRAMMAR OF ENTOMOLOGY. 



456. The shank (tibia) is a single piece, gene- 

 rally of about equal length with the femur, but 

 occasionally differing greatly in this respect : it is 

 usually three sided. 



457. The tibia is called winged (tibia alata) 

 when it is furnished with an attenuated dilated 

 process, much resembling the extended membrane 

 which constitutes the wing of a bat, but not so 

 flexible. 



458. The tibia is called corbiculate (tibia cor- 

 biculata) when it is furnished with a brush of stout 

 hairs, for the purpose of brushing the fallen off 

 flowers, and conveying it to its nest, as in bees. 



459. The tibia, in almost all insects, is furnished 

 with stiff spines or bristles, which are called spurs 

 (tibice calcaria). 



460. The foot (tarsus) consists of five joints, 

 called the first, second, third, fourth, and fifth 

 joints of the tarsus (planta, metaplanta, allux, 

 arthrium, ungula) ; the first (planta) being nearest 

 to the tibia, the others in regular succession. 



461. In pedunculated insects the five joints of 

 the tarsus are almost invariably present ; in other 

 insects one, two, or three of them are frequently 

 missing: when an insect has four joints to the 

 tarsus, the arthrium is wanting ; when only three, 

 the arthrium and pollux have disappeared. 



462. The ungula is armed at its extremity with 

 one, two, or four sharp curved claws (unguiculi) : 

 in the stag-beetle a sixth joint of the tarsus 



