THE LARCH WORM. 883 
A copy of Professor Hagen's letter is bere inserted : 
Museum of Comparative Zoology, 
Cambridge, Mass., July 7, 1881. 
The larva* belong to the Tenthredinida? (Hymenoptera), to Nematus erichsonii Hart. 
Iu the Canadian Entomologist, Vol. XIII, No. 2, p. 37, 1881, I have given a short no- 
tice concerning the same, sent last year from the Arboretum. The museum is very 
rich in Nematus, but does not possess this species, which is very rare in Europe, and 
has only twice before 1840 been observed to be very obnoxious to the larch in Hol- 
stein by Tischbein and iu the Harzby Saxesen. Ratzeburg, in his last work, remarked 
only that ic is rare, but may prove to be rather obnoxious. The species is, so far as I 
know, not described among the United States species, surely not under its original 
name. 
The following note by Dr. Hagen, extracted from the Canadian Ento- 
mologist, is the one referred to in the foregoing letter: 
Nematus erichsonii on Larix europcea. — A large number of larvae, very young to nearly 
full-grown, some probably full-grown, were sent living, with the twigs. The larvae 
agree perfectly with description and figure in Ratzeburg's Forst-Insecten, Tom. Ill, 
PI. 3, Fig. 4. The species is not represented in the collection here, neither in the larva 
nor in the imago state. It is not mentioned in Mr. Norton's catalogue of N. Am. Ten- 
thredinidse. I have to remark that the larva? of the three other species living iu Eu- 
rope on Larix, A r iz, Lyda laricis, Nematus soleus, and compressus, from their description, 
dp not agree with those sent to me. I am indebted to the Harvard Arboretum and 
its director, Mr. Charles S. Sargent, for these specimens. — Canadian Entomologist, 
Vol. XIII, No. 2, p. 37,1881. 
Its appearance in northern New Yorl\ — Mr. George Hunt, of Provi- 
dence, who is a close observer of plant and insect life, and who annually 
visits the Adirondack region in the vicinity of Scroon Lake, informs us 
that about July 25 and early in August the hackmatacks were seen to 
be entirely defoliated, no leaves being left on the trees by the 1st of 
August; he observed the effects of the worms at Horicon, Warren 
County, and Scroon Lake, in Essex County, as well as at Pottersville. 
The region affected was very extensive, covering many square miles in 
different swamps. No worms were observed in 1881. He has presented 
us with some of the worms, which are of full size, and do not differ from 
Maine specimens. They were fully grown July 28. 
Notwithstanding the efforts made to rear the larvae of this species 
last summer, no perfect insects were obtained, the cocoons furnished us 
by Mr. Atkins having been all parasitized by a species of Pteromalus, 
a parasite of the hymenopterous family Chalcididae ; while of two false 
caterpillars which spun cocoons, neither had hatched up to the time of 
writing. 
On referring to the great work of Katzeburg on forest insects, the 
admirable colored figure of the larva of Nematus erichsonii which he 
gives exactly represents the peculiar style of coloration of our worms ; 
we had identified it as perhaps this species, or as the young of one 
representing it in this country. 
It appears by the foregoing extracts that Professor Hagen had exam- 
ined the larva and had identified it as Nematus erichsonii. We are 
unable to find any differences in the larvje from the figure of the Euro- 
