138 CEHURA FURCULA. 



leaved willow, the leaves of which I have noticed are 

 sometimes distorted and discoloured by gall insects in 

 such a way as to offer considerable resemblance to 

 " kitten" larva?, and the mimicry of this appearance 

 doubtless in its degree goes to protect these larvae from 

 birds. 



I have never seen the egg : of the larva I took notes 

 at three stages ; but before I transcribe these notes 

 perhaps I may preface them by a word or two on the 

 nomenclature I use for the characteristic structure and 

 colouring of the Gerura larva?. The projecting warts on 

 either side of the head on the front of segment 2 are 

 of course not horns, but in the young larvae they look so 

 at first sight, and so I have called them ; the dorsal pat- 

 tern I call the saddle, and its extension down the side of 

 the eighth (and sometimes seventh and ninth) segment 

 would thus be flaps or stirrup-leathers ; the double 

 process standing out from segment 13, whence whip- 

 like filaments are protruded, I simply call tails ; these 

 I used to consider a modification of the anal prolegs, 

 but now, through Dr. T. A. Chapman's good teaching, 

 I regard them as dorsal appendages, somewhat after 

 the fashion of the anal spines of the larva3 of the 

 Satyridi, which of Course exist together with the anal 

 prolegs. Having had more opportunities of studying 

 the larva of C.vinula, I give most details of that species, 

 and make it my standard of comparison ; the Gerura 

 larva? always after a moult eat up the cast skin, except 

 the head cover, and the empty tubes of the tails. Dr. 

 Chapman considers that they thrive better if they also 

 consume the silk-spinning on which they fix themselves 

 during a moult. 



The youngest larvae I described were from 3*5 mm. 

 to 4 mm. in length, their tails 1*5 mm. long; the head 

 brown ; the back bright yellow on 3 — 5, dark brown on 

 6 and 7, pale yellow on 8, 9, and front of 10, and 

 brown again on the rest ; the sides pinkish brown. A 

 larva 12 mm. long had its tails nearly 6 mm. ; the 

 horns on 2 quite long, the dorsal saddle fully developed 



