FOOD-PLANTS OF THE CATERPILLARS 



131 



#re very small, although its body, "feelers," and legs are well 

 developed. By means of the latter it clings to the empty 

 chrysalis while its wings expand. A butterfly in this posi- 

 tion with its wings nearly expanded, is shown in Fig. 47, which 

 like all but one of the photographs of the insects illustrated 

 in this bulletin was taken from the living specimen. In the 

 course of half an hour the wings become fully developed, and 

 the butterfly is likely to crawl to some firmer support where 

 it will rest an hour or so before venturing upon its first flight. 



FOOD-PLANTS OF THE CATERPILLARS 



The caterpillars of the Mourning Cloak Butterfly are re- 

 stricted to comparatively few food-plants. In regions where 



f they are not especially 



abundant they are likely to 

 be found upon willow, pop- 

 lar, or elm. In general our 

 observations indicate that 

 they are as likely to be found 

 on any one of these food- 

 plants as upon either of the 

 other two; but in certain 

 localities where they become 

 especially abundant it seems 

 that they are more likely to 

 occur upon the elm. There 

 is considerable evidence to 

 show that they prefer the 

 American elm to other spe- 



Fig.47. Butterfly hanging to empty { f tfa although 



chrysalis as its wings expand. 



in the case of willow and 



poplar there seems to be little if any preference as to spe- 

 cies. Miss C. G. Soule has seen the butterflies depositing 

 their eggs upon the white and canoe birch, and in Labrador 

 and Europe it has been recorded as feeding upon a species 

 of birch. There is one record of the caterpillars having been 

 found feeding upon the hackberry (Celtis occidentalism , and 



