350 LEPIDOPTERA. 



brown stripes on all the wings between the nervures ; this 

 form is (naturally) always obtained at light, usually in a 

 room, and may at once be produced by passing an ordinary 

 fresh specimen quickly through a gas flame. 



On the wing in April, May, and June, and as a second 

 generation in July and August. 



Larva stout, very twig-like ; third segment swollen 

 laterally ; seventh with a large bifid dorsal protuberance ; 

 slight transverse prominences on the eighth, ninth, and 

 tenth, that on the ninth the largest, but one of them, or 

 even all three, sometimes wanting ; eighth and ninth seg- 

 ments of the undersurface each with two small tubercles or 

 rudimentary legs. Head squared above, slightly bifid, the 

 face vertically flattened ; ventral spots raised ; third pair of 

 legs extended in repose. Dull purple, shaded with pale grey 

 and red, but without markings ; face similar, top of the head 

 paler. 



Or — Dull brown, or blackish, dusted with green towards 

 each extremity, and having a pale greenish crescent-shaped 

 lateral marking on the third segment. 



Or — Dull dark grey with indistinct blackish diamond- 

 shaped dorsal pattern ; sides shaded with pale grey. 



Or — Ferruginous with indistinct pale bluish-grey dorsal 

 diamonds; sides of the middle segments clouded with 

 purplish-grey, and the dorsal line very faint grey. 



Or — Of the exact colour of a purple hawthorn-twig, with 

 the tips of the dorsal projections redder. 



All these forms graduate into each other. (C. Fenn.) 



September to April (hybernating), and as another genera- 

 tion in July and August, sometimes September. On haw- 

 thorn, and occasionally upon blackthorn and apple ; more 

 rarely on other fruit trees, wild-service (Sorlus torminalis), 

 whitebeam, and hazel ; feeding at night. 



By prolonged and careful experiments Professor Poulton 

 and Miss Lilian Gould have succeeded in proving that the 



