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from its favorite plant, so nearly resembles the slug-worm 

 saw-fly as not to be distinguished 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-gray, 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-twentieths 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 twentieth 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 

 tip their legs, and fall to the ground. The males are 

 more active, fly from one rose-bush to another, and hover 

 around their sluggish 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 con- 

 vex. They have a small, round, yellowish head, with a 



