LEGS. 



35 



ed, for the sake of exactness, the anterior legs ; when the 

 middle and hind pairs are collectively meant, the poste- 

 rior legs. The legs are composed 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 por- 

 tion of the legs, often provided with tubercles, spines or 

 projections or sometimes greatly thickened; usually 

 slender. 



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

 often with various ornamentations or projections. When 

 it terminates in one or more distinct, short, bristly spines, 

 it is said t<5 be spurred. 



Tarsus, the distal division of the legs, composed (ex- 

 cept 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 hook- 

 lets on the under side of the last tarsal joint, at the base 

 of which below, are a pair of 



Pulvilli (fig. 10), two pad-like, flesh}* cushions attached 



to the last joint of the tarsus 

 below the claw, usually pres- 

 ent, but often absent among 

 the Orthorrhapha and often 

 much larger and better de- 

 veloped in the male than the 

 female. They are sometimes 

 elongate, but are more usu- 

 ally rounded, and provided 

 with hairs. Between them is 

 the 





Fig. 10. Claws and pulvilli of 

 domestic fly. After Kellogg. 



Empodium, a median appendage on the under side of 

 and between the claws, either in the form of a pad, like 

 the pulvilli. (fig. 9-5 ), when it is called pulvilliform, or 

 like a bristle or spine (see Asilidae, fig. 31), sometimes 



