320 American Amphibia. 



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

 gular 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 rather 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 antennae 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 Glaucopidida. 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. IY. — On AmeiHcan Amphibia; by Abm. Sager, M. D. 



Detroit, (Mich.) March 5, 1839. 



TO PROF. 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 



