884 FIFTH REPORT OF THE ENTOMOLOGICAL COMMISSION. 



pean species, and the cocoons are of the size and form as figured by 

 Katzeburg. A description of the fully grown larva is not given by 

 Ratzeburg. The eggs are described by Ratzeburg (after Tischbein) as 

 about one-half a line {^"') long, white, transparent, laid in a row upon 

 and within the young larch shoots. The following is a free translation 

 of his description of the saw-fly, which he calls the large larch saw-fly, 

 and figures in Theil III, PI. Ill, Fig. 4. 



4 to 5'" long and wings expanding 10 to 11'". Iii sculpturing and coloring so great 

 a similarity with. N. sefiientrionalis $ that it would be mistaken for it were it not 

 for the tarsal scoop-like dilatation in latter species ; but there is in place of the wing- 

 band only a light shade in the largest cubital cell ; both the femoral hooks and apoph- 

 yses are almost clear, the wing-angle of the prothorax brownish white ; the whitish 

 femoral rings are only clear on the hinder legs, and ou the abdomen at most the four 

 middle rings are reddish-brown. The punctures are finer than in N. sepientr'ionalis^ 

 especially on the scutellum and on the rather shining mesosternum. 



Ratzeburg states that he himself has not observed this insect, which 

 occurs in Germany and other jjarts of Europe. It appeared on the 

 larch in the Harz Mountains as well as on the plains of Holstein. The 

 larvae are social, but do not occur in such thick, crowded clusters as do 

 those of Lophyrus. The flies make their appearance toward the mid- 

 dle of June. The eggs are laid usually in a single row on the upper 

 end of the young shoots, two or three sometimes being placed together 

 along the shoot. The eggs are inserted in a little slit made by the 

 ovipositor under the epidermis. They hatch at the end of June and early 

 in July, and the larvae stop eating, becoming fully grown, toward the 

 middle of August. They then fall from the trees and spin their cocoons 

 under the moss ; here they pass the winter, and in the following May 

 enter the chrysalis state within the cocoon, to appear as four-winged 

 flies in June. From a forestry i^oint of view, adds Ratzeburg, the insect 

 might become injurious since the larvue have already in certain seasons 

 abounded on the larches in sufficient numbers to attract the attention 

 of forestry officers in Holstein. 



The habits of the American worm are evidently like those of the 

 European species ; and it is very i^robable that the insect is common to 

 both Europe and Northeastern America. At any rate our species could 

 not have been introduced with European larches, since its ravages have 

 been committed in the wilder, less frequented portions of Maine, New 

 Hampshire, and New York, as well as on the sea-board in towns long 

 settled. In brief, the habits of our species are as follows : The eggs are 

 laid in the terminal young shoots of the larch from about the middle 

 of June, in Massachusetts, to the early part of July in Northern Maine, 

 the larvfe feeding on the leaves late in June and in July and early 

 August. By the last of July to the first week in A.ugust, according to 

 the latitude, the worms are nearly fully grown, while a few half-grown 

 ones occur on the trees in Maine in the last week of August and the 

 early days of September. It is very doubtful whether there are two 

 broods. We will now give a more detailed account of its habits. 



