ANCESTRY AND CLASSIFICATION. 



255 



FIG. 178. Spiral 



pa 



(Yestales) [Fig. 175], the tarsi are spineless and 



the joints reduced from five to one or two. In 



the highest family, the brush-footed 



butterflies [Fig. 176], atrophy of the 



front legs has reached both sexes, 



so that they are practically useless, 



although the atrophy is much more 



excessive in the male ; the legs of 



the female are greatly reduced in 



size, and lack the terminal arma- 



ture ; while in the male of the very * 0n ^ e 8 f 



highest groups [Fig. 177] they are 



exceedingly diminutive, and the tarsi 



are reduced to a single minute* joint. Now when 



we remember that this atrophy affects only the 

 legs borne by the first segment of the 

 thorax, and that this very segment, 

 and this only, has become greatly 

 reduced in size in passing from the 

 low larval stage to the perfect form, 

 we must accept atrophy of these legs 

 as a conclusive mark of high organi- 

 zation. 



If again we examine the spiral 



FIG. 179.-Spiral , 



tongue of Vanessa tongue W6 Sliall find, as W6 paSS 

 cardui, with pa- 



pillae, x 40. upward, a regular increase of com- 

 plication in the structure of the papillae, or organs 

 of taste. In the swallow-tails, as in the skippers 

 CFig. 178), these papillae are merely minute dis- 



