320 American Amphibia. 



middle of the wing, and on the under side there is a small trian- 

 gnlar spot near the base of the wing, and a short transverse one 

 beyond it which unites behind with the angular projection of the 

 large white patch. Expands ratlier more than one inch. 



I captured this beautiful insect on the wing at midday, in Mil- 

 ton, Mass., and have since seen it flying among the shrubbery at 

 Mount Auburn, Cambridge. There is also a broken specimen, 

 among Mr. Say's insects, which was taken in Indiana. My spe- 

 cimen is a male, as is also the one in Mr. Say's cabinet, and they 

 have the anal organs very large and hairy. Drury's specimen 

 seems to have been a female, for he says the anteimjE are seta- 

 ceous. It is possible that this insect is not one of the Sphinges 

 adscita; but I place it here on account of its diurnal habits, and 

 a certain resemblance, more easily seen than described, which it 

 bears to some of the Glancopidida:. It does not agree generically 

 with the types of Latreille's genus Callimorpha. When my 

 Catalogue of the Insects of Massachusetts was published, I had 

 not seen a colored copy of Drury's Illustrations, and failed to re- 

 cognize this insect in the uncolored one which I used. 

 Cambridge, Mass., Feb. 1, 1839. 



Art. IV. — On Am.erican Amphibia; by Abm. Sagek, M. D. 



Detroit, (Midi.) March 5, 1839. 



TO PROr. SILLIMAN. 



Sir — If the following observations upon some of the American 

 Amphibia, and description of some new ones, appear worthy of 

 publication, you will confer a favor by inserting them in your val- 

 uable journal. 



The structure and arrangement of the teeth, are of acknowl- 

 edged classific importance in distributing animals in a natural 

 series, and like most other characters are of variable importance 

 in different classes, depending upon the constancy and generality 

 of their existence, structure and arrangement. In the Class Am- 

 phibia, Lat., Order Batrachia, Brongn., they are generally regarded 

 as of generic value, (and here let me say that I have frequently 

 verified the truth of the observations of Drs. Davy, Weber and 

 others with regard to the biauriculate structure of the heart in this 



