[133] ON SOME SPECIES OF Cossus. 245 



From near the base of a prostrate birch at Center which had 

 been extensively mined, I took, in 1876, a pupa-case, clearly 

 differing from any known species. Unfortunately the speci- 

 men has been mislaid, or I should not hesitate, from the char- 

 acters it presented to describe it and give the species a name. 

 Other trunks of birch have been observed by me, similarly 

 mined, and evidently by the same Cossus. 



The species above described as Cossus undosus, may pos- 

 sibly be the O. populi of Walker (Cat. Lep. Br. Mus., vii, p. 

 1515), from Hudson's Bay, which has not yet been identified. 

 The very general terms in which its brief description is given, 

 will not admit of its separation from allied forms, and unless 

 the type is preserved in the British Museum, and comparison 

 be made, it must be handed over to the long list of undeter- 

 mined and indeterminable species of Walker. 



It cannot be the Cossus nanus of Strecker, from its non-re- 

 semblance to Cossus Hgniperdi) which C. nanus is said closely 

 to resemble* ; and from ^differing markedly from a Colorado 

 example of a $ Cossus which I refer to the $> named by Mr. 

 Strecker but unfortunately accompanied by the mention of 

 only a few specific features. 



Cossus plagiatus Walker. 



This species, briefly indicated, loc. cit., p. 1515 (1856), is 

 another unknown species. Mr. Grote in his List of the North 

 American Platypterices, Attaci, etc., p. 8 (1874), f refers it as 

 a synonym of Mac Murtrei (Boisd.), Icon. Regne An., pi. 85, 

 f. 2, marking it, however, as an unrecognized species. It 

 does not appear why this reference is made, and we may pre- 

 sume that it is based on a citation of Dr. Packard, in his 

 Synopsis of the Bombycidce of the United States where un- 

 der the synonymy of Xyleutes plagiatus, he quotes from the 

 Systematic List of Canadian Lepidoptera by W. S. M. D' Ur- 

 ban, the following : 



*Cossus nanus n. sp. Expands 1 inches. Has the appearance f a minature 

 Cossus ligniperda, is gray, of lighter and darker shades, and reticulated with 

 black lines which are most noticeable across the disk and on the terminal part of 

 wing. Secondaries uniform grayish. Beneath grayish, faintly reticulated. Hab. 

 Colorado. Proc. Acad. Nat. Sci. Phila., 1876. p. 151. 



f Read before the American Philosophical Society, Nov. 20th, 1874. 



j Proc. Ent. Soc. Phila., vol. iii, p. 390. 1864. 



Can. Nat. and Geol., Aug. 1860, p. 247 



