THE LARCH WORM. 879 
23. Semiothisa bisignata (Walk.) Observed Aug. 4, Brunswick, Me. 
24. Aplodes conifer aria Pack. 
25. Cleora sp. 
26. 10-lined pine-span worm, No. 82, Bulletin No. 7. 
INSECTS INJURIOUS TO THE LARCH OR TAMARACK. 
Larix americana. 
AFFECTING THE LEAVES. 
In Bulletin 7 of the United States Entomological Commission we 
enumerated all the insects known to affect or in any way to prey upon 
the larch or hackmatack. There were none then known to abound upon 
or to seriously injure this tree, which has heretofore been supposed to 
be as free as even the hemlock from insect pests. The hackmatack, as 
is well known, is one of the most important lumber trees in Maine, as it 
sends down a single large root, which grows laterally, forming a bend 
at right-angles to the trunk, so that it is used for u knees" in building 
vessels, the smaller trees being used for the same purpose in boat-build- 
ing. It is also used for railroad ties. 
The larch grows in wet swamps, or standing water, where the spruce 
or hemlock as well as pines would not flourish, hence its growth en- 
hances the value of extensive swampy tracts in Maine, where the water 
often stands all summer, even through the severest droughts. 
1. The larch saw-fly worm. 
Nematus erichsonii Hartig. 
Order Hymenoptera ; family Tenthredinid^e. 
(Plate ix, Fig. 1, la, lb, Ic, Id, and Plate xxvi, Figs. 1, la, 2, 3, 4, 6.) 
Its devastations in Maine. — Our attention was first called to this in- 
sect late in August, 1882, and we first saw the effects of its ravages at 
Brunswick, Me., where it had partly or entirely stripped the hackma- 
tacks in a very wet swamp on the banks of the Androscoggin Eiver, on 
the farm of Hon. 0. J. Gilman, who called our attention to the ravages 
which had been committed earlier in the season. On examining the 
growth in company with him, we found that most of the trees, both 
large ones, 6 to 10 inches in diameter, and small saplings, 6 to 15 feet 
in height, had been attacked j some of the trees were stripped, others 
partially so, while others had wholly escaped. The trees in the middle 
of the swamp appeared to have suffered most, while the smaller ones 
on the edge or on higher land were less injured. 
By jarring the trees a few young, half-grown worms of the second 
brood which had not yet undergone their last molt, and a single fully- 
grown larva were collected, while the cocoons from which the saw-flies 
