86 i September, 
species as it is to express adequately my grateful thanks to my kind friend Mr. 
Doubleday for the two fine examples sent me on the 5th June last, feeding on 
sallow — Salix ca/prwa. 
This larva is not slow in its movements, which are very graceful as it turns 
and accommodates itself to the various positions necessary to its progress amongst 
the leaves, eating rapidly and voraciously, cutting out a large portion of a leaf in 
a few seconds ; but it is easily alarmed, for a touch of the leaf or slight shake of 
the spray transforms it into a very different looking creature. Its structure cannot 
be well understood until it is walking or feeding ; then the flexile motions of the 
head become apparent, famished as it is on the crown with a pair of long forked 
tapering horns, blunt at their tijDS, curved oA their inner sides and concavely bent 
a little in front, and covered with raised points on their front surfaces ; they are 
much like those of a snail, but not retractile or moveable, though when the head 
is rapidly in action, as in feeding, so the horns are displayed perpendicularly or 
sloping backward and forward, or horizontal when at rest or in alarm. The crown 
is slightly notched and the face rather flattened above, but a little convex towards 
the lower part where it is widest. When full-grown and stretched out it attains 
the length of two inches, is rounded and tapering towards both head and tail, the 
anal segment terminating in an elongated, rather flattened point, which is, however, 
divided and slightly forked at its extremity ; the prologs short and thick, and a 
fringe of short hairs above them along the sides. The segments are sub-divided into 
five portions, the anterior being much the widest, and all studded with rows of 
minute raised points. 
When alarmed the segmental divisions and deep sub-divisions disappear, as it 
suddenly contracts its length, and are all drawn up so closely together as to make 
the raised points resemble the pile of a rich velvet : at such times, and when at 
rest, the head is bent down, the horns appear in a line with the body, the back 
much arched, thickened, and rounded, remaining a long time motionless, assimilating 
admirably with the leaf on which it rests. It reposes on a leaf, generally on the 
under-side, but not invariably so, and spins a quantity of silk, to which it firmly 
adheres. 
In colour, the larva is a bright full green on the back and sides, as far as the 
sixth segment, thence blending gradually into a yellower green, and the three 
last segments much paler, the whole surface studded with minute yellow points. 
On the back of each horn, and extending along the second, third, and fourth 
segments, is a sub-dorsal stripe of pinkish or yellowish flesh colour ; and on each 
side of the other segments, as far as the tenth inclusive, a thin oblique stripe of 
dull yellow slightly edged with red, running backwards from the spiracular region 
of one segment to the sub-dorsal region of the next ; the most conspicuous is that 
which begins on the sixth and ends on the back of the eighth segment, being longer 
and thicker, especially at the end, which is bordered above by a purplish-brown or 
crimson mark ; the raised points there being much longer and larger than those on 
the other lines, as they also are longer than those of the green surface. 
A pale yellowish lateral stripe on the anal segment, extending to the tips. 
The spiracles are red, and below them the green softens into a pale whitish-green, 
with a fringe of white silky hairs above the prologs ; these last are of a pale trans- 
parent bluish-green, the ventral surface whitish. The head, behind, is the same 
