29 
plant is our commonest city tree, the Ailanthus, and the cul- 
ture of the insect is easy; the silk is strong, lustrous, and, 
in the raw state, of a pale grey tint. Mr. Akhurst had 
carried his experiments as far as energy and enthusiasm 
could avail; and all that is wanting now to the full solution 
of the problem is capital. If some persons possessed of 
means would enter into the investigation, the question as to 
whether the silk can be profitably used for manufacture 
could be speedily decided. 
The PrEsIDENT laid before the Lyceum, for the inspection 
of the members, the new geological map of the entire territo- 
ry of the United States, compiled by Prof. C. H. Hitchcock ; 
and spoke of it as an improvement upon anything of the kind 
previously issued, and as meeting a long-felt want. 
Prof. D. S. MARTIN exhibited the closing part of the first 
volume of Prof. Wm. H. Edwards’ work on the Butterflies of 
North America, He called attention particularly to the very 
interesting and suggestive discoveries of Prof. Edwards in 
reducing, in several instances, two or three so-called species 
which had been regarded as distinct, to seasonal, or other, 
modifications ofa single species. This fact was proved in part 
IX of the present volume, with regard to several familiar 
butterflies. Grapta interrogationis, Fabr., for instance, and 
G. umbrosa, Lintner, are but well-marked varieties; as Mr. 
Edwards has raised them both in abundance from eggs laid 
by individuals of G. wmbrosa. He therefore proposes the 
name Wabriciw to denote the lighter-colored form, originally 
described by that eminent entomologist, while the name 
umbrosa, given to the dark individuals by our corresponding 
member, Mr. Lintner, remains, both being but varieties of the 
species interrogations. 
Inthesame way, Papilio Ajax presents three distinct season- 
al types, two of which, at least, have been regarded as separate 
species, P. Marcellus, P. Telamonides, and P. Walshit. The two 
last named appear in the spring, from pupze that have lived 
