The Life-History and Anatomy of Butterflies 



Fig. 20. — Caterpillar of Basilarchia disippus, 

 the viceroy, natural size (Riley). 



called the anal prolegs. These organs, which are necessary to 

 the life of the caterpillar, do not reappear in the perfect insect, but 

 are lost when the transformation from the caterpillar to the 

 chrysalis takes place. There are various modifications of this 

 scheme of foot-like appendages, only the larger and more highly 

 developed forms of lepidoptera having as many pairs of prolegs 

 as have been enumerated. 



The bodies of caterpillars are variously ornamented: many 

 of them are quite smooth; many are provided with horny 

 projections, spines, and eminences. The coloration of cater- 

 pillars is as remarkable in the 

 variety which it displays as is 

 the ornamentation by means 

 of the prominences of which 

 we have just spoken. As 

 caterpillars, forthe most part, 

 feed upon growing vegeta- 

 tion, multitudes of them are 

 green in color, being thus 

 adapted to their surroundings 

 and securing a measure of 

 protection. Many are brown, and exactly mimic the color of the 

 twigs and branches upon which they rest when not engaged in 

 feeding. Not a few are very gaily colored, but in almost every 

 case this gay coloring is found to bear some relation to the color 

 of the objects upon which they rest. 



Caterpillars vary in their social habits. Some species are 

 gregarious, and are found in colonies. These frequently build 

 for themselves defenses, weaving webs of silk among the 

 branches, in which they are in part protected from their enemies 

 and also from the inclemencies of the weather. Most caterpillars 

 are, however, solitary, and no community life is maintained by 

 the vast majority of species. Many species have the habit of 

 drawing together the edges of a leaf, in which way they form 

 a covering for themselves. The caterpillars of some butter- 

 flies are wood-boring, and construct tunnels in the pith, or 

 in the soft layers of growing plants. In these cases, being 

 protected and concealed from view, the caterpillars are gener- 

 ally white in their coloration, resembling in this respect the 

 larvae of wood-boring beetles. A most curious phenomenon has 



8 



