BOARMID.'E—NYSSIA. 149 



tion of the upper, exc<'pt that a deep bhick narrow discal 

 streak is conspicuous on all the wings ; body covered with 

 shaggy whitish-brown hairs; leg-tufts and legs purplish- 

 brown, the tarsi barred with white. 



Not very variable except in intensity of colour, from white 

 with the nervures pale yellow-brown and the stripes exceed- 

 ingly faint, to a grey ground colour, with strong thickened 

 black markings. The whitest specimens with the brightest 

 markings are obtained from Ireland. 



On the wiug in March and April. 



Larva even in breadth, almost cylindrical, without pro- 

 tuberances ; head rounded, grey, marbled with darker lines ; 

 dorsal region green or grey-green, excessively marbled and 

 irrorated with minute grey or grey-black irregular lines and 

 dots, among which the dorsal line, double but equally irregu- 

 lar, is sometimes visible, especially upon the anterior seg- 

 ments; edging this marbled dorsal and subdorsal area on 

 each side is an almost equally irregular black longitudinal 

 Ime which makes an arch over each spiracle, and also forms 

 the upper margin of a broad bright yellow spiracular stripe, 

 which is again edged below by a greenish-black stripe; 

 undersurface black with two middle stripes of dusky-grey ; 

 over each black leg and proleg is a yellow curved streak. 

 There is but little change in the colour and appearance of 

 this larva from its early youth upward. 



May till -July or Auguab ; on sallow, bird's-foot trefoil, 

 dandelion, dock, thistle, plantain, clover, grasses, birch (in 

 continement), yarrow, Ccniaurca, Salvia, knotgrass, and colts- 

 foot ; apparently almost any low-growing plants ; feeding at 

 night, remaining during the day upon its food in an arched 

 position, holding with both legs and prolegs, but if disturbed 

 dropping by a thread, and remaining suspended, or lying 

 doubled together on the sand. 



Pupa short and stout, very thick in the middle, tapering a 

 little at the head, and rapidly at the abdomen ; limbs closely 



