172 BUTTERFLIES 



resting with expanded wings in the sunniest spots. These 

 butterflies obviously have endured the coldest weather and 

 if they are to survive until another season must continue to 

 endure still more. This species is commonly called the 

 Mourning-cloak butterfly — ^not a particularly happy name 

 for so beautiful an insect. In England it has the more 

 suggestive title of Camberwell Beauty, and country boys 

 are said to call it the Yellow Edge butterfly. Its general 

 life-story has already been told on pages 112-115. 



The caterpillars of the Mourning-cloak butterflies are 

 restricted to comparatively few food plants. In regions 

 where they are not especially abundant, they are likely to 

 be found upon willow, poplar, or elm. In general, as many 

 observations indicate, they are as likely to be found upon 

 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. On this account they have been called the 

 Spiny Elm caterpillars. There is considerable evidence to 

 show that they prefer the American elm to other species of 

 the genus, although in the case of willow and poplar there 

 seems to be little if any preference as to the species. 



Miss Caroline G. Soule has seen the butterflies deposit- 

 ing their eggs upon the white and canoe birch, and it has 

 been recorded as feeding in Labrador and Europe upon a 

 species of birch. There is one record of the caterpillars 

 having been found feeding upon the hackberry, and also of 

 their having fed greedily upon the leaves of rose bushes, and 

 still another of their having almost defoliated a pear tree. 

 Linden and nettle are also included in the European lists 

 of the food plants of this species. (See plates, pages 1A5, 1 76.) 



It is evident, however, that all of these, except the three 



