TRIFIDA-:. 277 



and edged with black ; between these is a triangular grey-' 

 black cloud arising from the costal margin ; extreme hind' 

 margin edged with a black line ; cilia long, shining slate- 

 grey clouded with darker. Hind wings unusually large •, 

 apex and hind margin strongly rounded ; texture thin ; 

 colour shining white ; nervures faintly dusted with brown ; 

 hind margin edged with a dark brown line ; cilia long; white, 

 but the basal portion shaded with brown. Female rather 

 smaller — sometimes decidedly so — fore wings more regularly 

 narrow, extremely glossy, but darker slate-grey ; the first 

 and second lines both complete, black ; the margins of the 

 two stigmata and the blotch between them glossy black ;. 

 hind wings smaller and rather shaded with grey-brown ; 

 body shorter but very little thicker. 



Underside of the fore wings shining smoky-black or grey- 

 black, darkest at the costa, which, however, is dotted and 

 streaked toward the apex with dusky white. Hind wings 

 white, dusted with grey-brown over the costal region ; body 

 purplish-grey-brown; legs very long, but slightly tufted, 

 purple-brown barred with yellowish-white. 



Not very variable, except that the female is sometimes 

 blackish-slate with hardly any markings. On the other 

 hand, in western districts, and especially in Ireland, both 

 sexes are occasionally large in size, with unusually distinct 

 markings. 



On the wing in August and September. 



Larva nearly uniformly cylindrical; head rounded and 

 polished, of about the same width as the second segment ; 

 segmental divisions well defined ; skin soft and smooth, but 

 not glossy ; ground-colour warm pale chestnut brown ; head 

 greyish-brown, thickly freckled with dark brown ; two 

 purplish-brown lines (black at the divisions of the hinder 

 segments), enclosing a yellow line between them, form the 

 dorsal stripe ; subdorsal stripes yellow, very finely edged 

 with a darker shade of brown than the ground-colour; 



