52 6 
HYMENOPTERA. 
eggs, turn a little on one side, unsheathe their saws, and 
thrust them obliquely into the skin of the leaf, depositing, 
... in each incision thus made, a single egg. The 
Fig. 246. 7 ° 
i young (Fig. 246) begin to hatch in ten days 
or a fortnight after the eggs are laid. They 
may sometimes be found on the leaves as early as the first 
of June, but do not usually appear in considerable numbers 
till the 20th of the same month. How long they are in 
coming to maturity, I have not particularly observed ; but 
the period of their existence in the caterpillar state probably 
does not exceed three weeks. They somewhat resemble 
young slug-worms in form, but are not quite so convex. 
They have a small, round, yellowish head, with a black 
dot on each side of it, and are provided with twenty-two 
short legs. The body is green above, paler at the sides, 
and yellowish beneath ; and it is soft, and almost trans- 
parent, like jelly. The skin of the back is transversely 
wrinkled, and covered with minute elevated points ; and 
there are two small, triple-pointed warts on the edge of the 
first ring, immediately behind the head. 
These gelatinous and sluggish creatures eat the upper 
surface of the leaf in large irregular patches, leaving the 
veins and the skin, beneath, untouched ; and they are some- 
times so thick that not a leaf on the bushes is spared by 
them, and the whole foliage looks as if it had been scorched 
by fire, and drops off soon afterwards. They cast their 
skins several times, leaving them extended and fastened on 
the leaves ; after the last moulting they lose their semitrans- 
parent and greenish color, and acquire an opaque yellowish 
hue. They then leave the rose-bushes, some of them slowly 
creeping down the stem, and others rolling up and dropping 
off, especially when the bushes are shaken by the wind. 
Having reached the ground, they burrow to the 
Fig. 247. » b ; 
depth of an inch or more in the earth, where 
each one makes for itself a small oval cell (Fig. 
247), of grains of earth, cemented with a little gummy silk. 
