INSECTS. 
81 
therefrom except by a practised observer. It is also very much like 
Selandria barda , vitis and pygmcea, but has not the red thorax of these 
three closely-allied species. It is of a deep and shining* black color. 
The first two pairs of legs are brownish grey or dirty white, except 
the thighs, which are almost entirely black. The hind legs are black, 
with whitish knees.. The wings are smoky and transparent, with 
dark-brown veins, and a brown spot near the middle of the edge of 
the first pair. The body of the male is a little more than three twen¬ 
tieths of an inch long, that of the female one fifth of an inch or more, 
and the wings expand nearly or quite two fifths of an inch. These 
saw flies come out of the ground, at various times, between the twen¬ 
tieth of May and the middle of June, during which period they pair 
and lay their eggs. The females do not fly much, and may be seen, 
during most of the day, resting on the leaves j and, when touched, 
they draw up their legs, and fall to the ground. The males are more 
active, fly from one rose bush to another, and hover around their slug? 
gish partners. The latter, when about to lay their eggs, turn a little 
on one side, unsheath their saws, and thrust them obliquely into the 
skin of the leaf, depositing in each incision thus made a single egg. 
The young 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 twentieth 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 the 
young of the saw fly 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, a7td yellowish beneath; and it is soft, and 
almost transparent 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, immedi¬ 
ately 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 sometimes so 
thick that not a leaf on the bushes is spared by them, and the whole 
toliage looks as if it. had been scorched by fire, and drops off soor 
4* 
