THE LARCH WORM. 883 



A copy of Professor Hagen's letter is here inserted : 



Museum of Compakative Zoology, 



Cambridge, Mass., July 7, 1881. 

 The larvje belong to the Tenthredinida? (Hynienoptera), to Nematns erichsonii Hart, 

 lu 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 Arboretnm. The nmseum is very 

 rich in Nematns, 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 in the Harz by Saxesen. Ratzebnrg, in his last work, remarked 

 only that it 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 ia the imago state. It is not mentioned in Mr. Norton's catalogue of N. Am. Ten- 

 thredinidie. I have to remark that the larv;e of the three other species living in Eu- 

 rope on Larix, viz, Lyda laricis, Nematus soleus, and compressus, from their description, 

 do 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 Yor-l:. — 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 larvoe 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 Chalcididte; while of two false 

 caterpillars which spun cocoons, neither had hatched up to the time of 

 writing. 



On referring to the great work of Ratzeburg 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 

 represeuting 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 larvae from the figure of the Euro- 



