THE CATERPILLAR. 



Fro. 37. Ribbon-like 

 bristle of young cater- 

 pillar of Cercyonis 

 Alope, X 125. 



[Fig. 37] ; on the abdominal segments these hairs 



point backward, and on the thoracic forward; 



that is, the caterpillar parts its 



hair in the middle [Fig. 38]. In 



the Monarch or Milk- weed but- 



terfly (Danais Plexippus) the 



full-grown caterpillar (see Fig. 



22) is naked, but adorned with a 



pair of long, thread-like, fleshy, 



flexible tentacles at either extremity of the body ; 



in the young caterpillar these tentacles or fila- 

 ments are ab- 

 sent, but their 

 future position 

 is marked by lit- 

 tle, conical, 

 black points, 



while the body is covered with minute black 



bristles, arising from still more minute warts, and 



arranged six on the back of each 



segment, placed four in a row in 



front and one on each side behind, 



and three on either side of the body, 



one in the middle of the segment 



and two below [Fig. 39]. In our 



purples the segments of the young 



caterpillar are equal in size and have 



regular series of stellate warts ; in the mature 



caterpillar the body is grotesquely hunched, while 



FIG. 38. Young caterpillar of Cercyonis Alope, 



X 20. 



FIG. 39. Side 

 view (a) and top 

 view (b) of young 

 larva of Danais 

 Plexippus to show 

 the arrangement 

 of the hairs, X 20 

 (Riley). 



