INTRODUCTION. XIX 



LEGS. 



The three pairs of legs are attached to the prothorax, meso- 

 thorax and metathorax, and are called, respectively the front, 

 middle and hind pairs. When the front and middle pairs are 

 spoken of together they should be called, for the sake of ex- 

 actness, the anterior legs ; when the middle and hind pairs 

 are collectively meant, the posterior legs. The legs are com- 

 posed of five parts : 



Coxa, the part attaching the legs proper to the thorax. 



Trochanter, the short, small, ring-like portion between the 

 femur and coxa. 



Femur, almost invariably the longest and stoutest portion 

 of the legs, often provided with tubercles, spines or projec- 

 tions or sometimes greatly thickened ; usually slender. 



Tibia, the next part succeeding the femur, and like it often 

 with various ornamentations or projections. When it ter- 

 minates in one or more distinct, short bristly spines, it is 

 said to be spurred. 



Tarsus, the distal division of the legs, composed (except in 

 some abnormal forms) of five joints, of which the first, that 

 next to the tibia, is called the metatarsus. On the terminal, 

 or fifth joint, are the 



Ungues or claws, usually two, curved movable booklets on 

 the under side of the last tarsal joint, at the base of which 

 below, are a pair of 



Pulvilli, two pad-like, fleshy cushions attached to the last 

 joint of the tarsus below the claws, usually present, but often 

 absent among the Orthorrhapha and often much larger and 

 better developed in the male than the female. Between them, 

 among a number of the families of the Cyclorrhapha, is the 



Empodium, a median appendage on the under side of and 

 between the claws, either in the form of a pad, like the pul- 

 villi, when it is called pulvilliform, or like a bristle or spine ; 

 rarely it is alone present and the pulvilli wanting. 



