28 BOARMIA ROBORARIA. 
stituted ; and to these the larvee (then having attained 
a length of three-quarters of an inch) attached them- 
selves by silken threads spun over the twigs, the 
threads being then grasped by the claspers; in some 
instances the threads were also even spun over the 
hinder segments of the larvee. In this position they 
spent the winter in a semi-torpid state, but in mild 
weather fed with evident relish on the tender bark, 
sometimes eating nearly through the twigs. In early 
spring many of them died off; and the only one which 
reached maturity was full-grown early in June, when 
I described it as follows: | 
Length about two inches, and of average propor- 
tionate bulk. Head flat, and deeply notched on the 
crown, narrower than the second segment, into 
which, when the larva is at rest, it is partially with- 
drawn. Body cylindrical, of tolerably uniform width, 
but with several prominences, as follows: the fifth 
segment is swollen from the sides into two conspicuous 
dorsal humps, divided by a notch on the centre of the 
dorsal surface ; on the sixth segment is a transverse 
ventral ridge; and on the twelfth are two very small 
dorsal humps; there are also two short anal points. 
Skin tough and rather shining, puckered on the anterior’ 
and posterior segments, but smooth on the middle of 
the dorsal surface. The ground colour is marbled 
with almost every shade of pale brown, tinged in 
several places with dul! dark green, and blotched along 
the sides with pale bluish-grey. Head chocolate- 
brown, the face mixed with grey. Medio-dorsal stripe 
interrupted and indistinct, a little darker than the 
ground colour; subdorsal and _ spiracular stripes 
scarcely perceptible. Spiracles distinct, pinkish- 
brown, encircled with chocolate. The ground colour 
of the ventral surface is variegated with the 
same shades of brown as the dorsal surface, but 
has in addition several purplish marks; on each 
side of the ridge on the sixth segment is a pale 
yellow mark; there is also the rather broad, 
