238 LEPIDOPTERA. 



a much deeper ground colour of red-bi^own, and a decided 

 tendency in the same direction exists in the western and 

 more northern districts of England. As in some other 

 species, a peculiarly dark form has made its appearance in 

 South Yorkshire, probably within the last forty years. Mr. 

 G. T. Porritt, who has been paying attention to it at intervals 

 for more than twenty years, tells me that in woods near 

 Huddersfield, where it used occasionally to occur among 

 abundance of typical specimens, it is now comparatively 

 common. In it the fore wings have become smooth shining 

 dark fuscous, or black-brown, the thorax the same colour, 

 while the hind wings in some individuals are still pale, but 

 in the majority are deeply tinged with smoky-black ; all the 

 markings in both having disappeared. The females seem 

 to have assumed this tendency still more strongly, for nearly 

 every specimen in the same localities is now dark, the body 

 and basal half of the winglets being sooty-black and the 

 outer half dark brown or smoky pale brown. With the males 

 are intermediates between these and the normal forms, but 

 such in the case of the females seem rare. The dark race 

 appears to be spreading, since it has now been taken near 

 Leicester, near Birmingham, and in Derbyshire, as well as 

 in plenty at Huddersfield, Rotherham, Wakefield, and else- 

 where in South Yorkshire. Scottish specimens do not 

 appear to partake of this darkening tendency. 

 On the wing in March and April. 



Larva elongated, cylindrical ; head flattened in front, 

 dusky-red, the face spotted with black, and having a whitish 

 transverse line above the mouth; general colour dull yellow, 

 olive-green, or greenish-brown; a series of dark grey X-like 

 dorsal markings is most distinct on the sixth to the twelfth 

 segments, on which last is a black transverse line ; on the 

 anterior segments is a broad purplish or greyish subdorsal 

 shade, sometimes with a faint geminated yellowish dorsal 

 line ; spiracles white, each placed in a black cloud, the inter- 



