NOTODONTID^. 109 



N. dictcca but with a long, distinct, wedge-shaped, pure white 

 streak near the anal angle and continued to the cilia. 



Besembling N. dictcva in structure, colour, and markings 

 so closely that the description already furnished of that 

 species applies to this, with the following exceptions : — the 

 colour of the fore wings in the present species is usually of a 

 clearer white with less brown or grey clouding ; the nervures 

 are not white except at their extreme tips ; the ringed white 

 discal spot is absent but replaced by one or two faint 

 brownish flecks ; and the long white streak which runs 

 to the hind margin, above the anal angle, is of a clearer white, 

 broader, much more distinctly wedge-shaped, and runs 

 through to the cilia, obliterating the black marginal line. In 

 the hind wings the colour is not so clearly white but tinged 

 with grey, and the blotch at the anal angle is not divided by 

 nervures nor by a white line but shades off in a dusky 

 clouding above ; cilia dappled with brownish. Underside, 

 darker than in N. dictcea, the fore wings almost wholly grey- 

 brown, except a sharply defined clear-white blotch just 

 below the apex, and sometimes a white streak on the very 

 dark costa ; otherwise similar. 



Variation very slight, but Scottish specimens are whiter 

 than those from the South, and reared specimens are often 

 paler than those captured at large. Dr. K. Freer has 

 specimens, taken on Cannock Chase, in which the longitudinal 

 black stripe is unusually broad, and its edging of brown 

 shading also rather extended. 



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

 second generation in July and August. Apparently single- 

 brooded in the northern portion of its range, but irregular 

 and uncertain, individuals fed up at the same time emerging 

 at very different periods, from May to September. 



Larva elongated, skin highly polished, twelfth segment 

 raised into a peaked hump which when young is very 

 prominent ; third segment swollen laterally ; head rounded 



