66 THE BUTTERFLY. 



is sometimes found on the hind shanks ; certainly 

 it originates at the same spot. 



The tarsi, or feet, are normally composed of five 

 joints, of which the first is usually as long as all 

 the rest, and in the male is occasionally swollen ; 

 with this exception they are slenderer than the 

 shank, and their combined length generally ex- 

 ceeds it [see Figs. 173-177] ; they are scaled and 

 more or less spiny like the shank, and a pair of 

 the terminal spines of each joint usually exceed 

 the others in- length ; the extremity of the last 

 segment, however, is armed in a different way by 

 claws, paronychia, and foot pads ; the claws are a 

 pair of divergent curving hooks, each hook some- 

 times deeply cleft so as to be double ; the pa- 

 ronychia, or whitlows, are curious membranous 

 expansions, which almost encircle the base of the 

 claws and are developed in various ways, at the 

 sides, or beneath, into flexible imitations of 

 them ; sometimes they are wholly obliterated, 

 but they are generally either absent or somewhat 

 similarly developed in all the members of the 

 same large group. The foot pads are fleshy mem- 

 branous flaps, often pedunculated, attached to the 

 base of the claws, and serving as soles for the 

 feet ; these, too, are sometimes wanting, especially 

 where the paronychia are absent. 



As a general rule the six legs are similar in 

 structure and proportions ; but further on [see 



