886 FIFTH REPORT OF THE ENTOMOLOGICAL COMMISSION. 



than when the eggs are first deposited. It would thus appear that 

 ovipositiou takes place about a week later iu the vicinity of Brunswick, 

 Me., than in Essex County, Mass., and about a week later iu north- 

 ern Maine and New Hampshire than on the coast at Brunswick. 



When the larva hatches, the incision gaps open, leaviug an oval hole. 

 Out of this gap the larva creeps, and itTarely eats the terminal shoot, 

 but crawls upon the leaves of the whorls next to the terminal shoot. 

 At first it nibbles oue side of the needle or leaf, leaving it half eaten 

 and rough, serrate, and partly withered along the edge. The half- 

 eaten, withered leaves of unequal length in a whorl on the end of the 

 smaller branches enable one to detect the presence of the young worms 

 on the tree. 



Usually after the young larvae have shed their first skin, they collect 

 on the verticils of the larch aud almost invariably begin to eat the 

 needles, one after another, beginning at the distal end and eating the 

 leaf obliquely until only a short stump is left; in this way one verticil 

 after another is eaten, and when the worms are half-grown they occa- 

 sionally collect around the main stem of the twig iu singular clumps or 

 clusters, the hiuder part of the body curled over their backs, and, owing 

 to their oblique posture in reference to one another, appearing like a 

 ball of worms. This singular appearance was briefly noticed by Eatze- 

 burg. The castings, or excrement, are long, cylindrical, more or less trun- 

 cated at each end. Our saw-fly differs slightly, as has been described, 

 from the German in the eggs being laid at the base of the leaves on 

 the newly-grown shoots, rather than on or just under the epidermis of 

 the last year's shoots, where we have repeatedly and in vain searched 

 for them. The larvae were observed to hatch out from June 20 to 30 at 

 Brunswick, Me. 



The larvae appear to attain their full size iu about five to seven days 

 after hatching ; certainly less than or uot more than ten days. There 

 appear to be but three molts or changes of skin, i. e., four stages of the 

 larvae. In casting the skin, the head splits open along the median line 

 of the vertex, and the epicranium or sides of the head split apart on each 

 side, leaving the clypeus and labrum in place ; then the body is drawn 

 out of the rent, the skin adhering to the needle or leaf. 



The efjT/;.— Slender, cylindrical, tapering rapidly towards each end. Length, 1.2™™. 



Larva at the time of hatching.— The head very large, much wider and higher than the 

 body before the latter falls out from eating; dusky or smoky green, not black, darker 

 in front on the clypeus and labrum than elsewhere; eyes black; thoracic legs smoky 

 o-reen. Body uniformly pea-green: the head and thoracic legs soon become darker, 

 and the body fills out aud becomes a little larger after the larva has taken food. 

 Length, 3-3.5""". 



Larva after the first molt.— Body pale green, without the glaucous pearly bloom of 

 the two later stages; head aud thoracic feet black; the segments wrinkled as in the 

 adult; but the short black spines of the two later stages are not to be seen. Length, 

 5-7""". 



Larva after the second molt.— It now has the peculiar glaucous green bloom of the 

 adult on the upper part of the body, the body being pale pea-green beneath and low 



