74 XANTHIA CERAGO. 



No doubt this confusion had arisen in part from my 

 having taken two or three figures at different times of 

 solitary examples too far matured ; recent experience 

 having demonstrated that when they are full-fed, or 

 nearly approaching that condition, their distinctive 

 characters have faded away, and their identification is 

 then hopeless. I have therefore thought that a 

 description of both X. cerago and X. silago may be of 

 use to some who, perhaps, like myself, have hitherto 

 been unable to distinguish the one larva from the 

 other as they chanced to come under notice. 



My sincere thanks are justly due for the kindness 

 and liberality I experienced on the 29th of April from 

 Dr. F. Buchanan White, of Perth, and on May the 4th 

 from Mr. George Baker, of Derby, they having both 

 sent me an abundant supply of sallow catkins con- 

 taining young larvse of both species ; and I may 

 mention that thenceforth these larvae all fed and throve 

 well on sallow leaves, and the moths appeared from 

 the 30th of July to the 14th of August. 



In both species the body of the larva is cylindrical, 

 having the segments plump and deeply defined, and 

 tapering a little anteriorly ; the head decidedly smaller 

 than the second segment ; the hinder segment tapering 

 also, and the anal pro-legs very close together beneath 

 its extremity. 



The larva of X cerago has on the upper surface, as 

 far as the black spiracles, a ground colour of reddish- 

 brown or purplish -brown, and beneath the spiracles a 

 much paler tint of the same ; the ventral surface pale 

 greyish- violet with a slight tinge of bluish-green on 

 the anterior segments; the whole upper surface is 

 freckled with dark brown excepting the segmental 

 divisions, which, when stretched out, are seen to be 

 unfreckled, and of rather a violet tinge. 



The dorsal line, when visible, is pale brownish- 

 ochreous, often obscured by the two dark brown lines 

 that enclose it, and these often run together in a dark 

 brown spot at the beginning of each segment, are lost 



