SESIIDAC. 8i 



fine hairs. Head pale brown, dorsal plate wliitish with two 

 brown spots ; body pinkish white tinged with yellowish 

 behind, with a slender dark brown dorsal hne, and with 

 faint transverse brownish lines or wrinkles on each sea'ment. 

 Legs black; prologs very short, whitish; spiracles black; 

 anal segment bristly, 



August to May in a burrow under the bark of large, old, 

 rough-barked birch trees, feeding on the inner bark. 



Pupa elongated, of rather even thickness, with prominent 

 antenna and wing-cases, and a horizontal ridge just in front 

 of the eye-cases. Abdominal segments with rows of short 

 spines. General colour dark shining brown, with the ridge 

 and eye-cases darker, the wing-cases edged with chestnut, 

 and the abdomen banded with paler brown. In a thick 

 ovate reddish cocoon of silk and raspings of wood, placed at 

 the end of the burrow, and immediately under the surface of 

 the thick bark, the skin of which is gnawed to a mere pellicle, 

 through which the pupa forces the front part of its body when 

 ready to produce the moth. There is scarcely a trace ex- 

 ternally of the presence of the pupa, and when discovered it 

 is hard work to cut it out safely from the old rough bark. 

 The cocoon is usually about four or five feet from the ground, 

 always in the trunk of the tree. 



The moth is said to emerge in the early morning sunshine. 

 It is timid, and on being disturbed throws itself off back- 

 wards and falls to the ground, hiding among the herbage 

 or undergrowth. First found about the year 1854 at Llan- 

 gollen, North Wales, where there appears to have been a 

 considerable colony in some very large old birch trees. Here 

 in the course of three seasons at least fifty specimens seem 

 to have been secured. At the death of the captor, Mr. 

 Ashworth, the locality was lost, but was re-discovered by the 

 late Messrs. E. Birchall and N. Cooke in 1862, and other speci- 

 mens taken ; then the trees were cut down and the insect was 

 again lost, though from the capture of a single specimen 



VOL. u, Y 



