TRIFID.E. 305 



narrower than the third segment, yellow-brown, strongly 

 marked with black, especially so in a streak from the top 

 of each lobe ; body rounded, each segment slightly swollen ; 

 of nearly uniform thickness from the fifth to the twelfth 

 segment, otherwise tapering off ; colour down to the spiracular 

 region purplish-brown ; a narrow polished black plate on the 

 second segment ; dorsal line almost clear white and very 

 conspicuous ; subdorsal lines indistinct — except in the dorsal 

 plate, where they show clearly — composed of a faint inter- 

 rupted series of bluish-white streaks and dots ; on each 

 segment between the dorsal and subdorsal lines is a large 

 square purplish-black marking, these, with the pale dorsal 

 line, forming the most noticeable features in the larva. There 

 are no perceptible spiracular lines, but the spiracles are black 

 and very distinct ; raised dots small and indistinct, of the 

 pale colour of the subdorsal lines ; ventral area and prolegs 

 uniformly dingy glaucous-green with a purplish tinge ; legs 

 pale straw-colour, and having immediately in front and 

 behind each of them a short black streak, (G. T. Porritt.) 



April and May, on birch and sallow, and in captivity has 

 been known to feed upon Canadian poplar. Its habits at 

 large do not seem to have been noticed. 



In the egg-state through the winter. 



Pupa apparently undescribed, except that it is said by 

 Dr. Chapman to be very like that of Glcca vaccinii, but more 

 slender and tapering ; also liaving the cremaster larger 

 and longer, wrinkled, and armed with a lyre-shaped pair 

 of spines, with a secondary pair of shorter spines outside 

 them. 



The moth flies at dusk, and comes readily to sugar and to 

 the blossoms of heather, ragwort, and rush. Doubtless it 

 hides among herbage during the day. Principally confined 

 to woods and heaths in which birch is common, and either 

 local or scarce ; but in certain years, in its more favoured 

 localities, it occurs in extraordinary numbers. Such was the 



VOL. V. u 



