INSECTS. 81 



therefrom except by a practised observer. It is also v-ery much like 

 Selandria harda, vitis and pygnuea, 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 ; 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 httle 

 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, and 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 aro 

 two smaU, 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 

 foliage looks as if it had been scorched by fire, and drops off soon 

 4* 



