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 antenne 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 Gilducopidide. It does not agree generically 
with the types of Latreille’s genus Callimorpha. When my 
Catalogue of the Insects of Massachusetts was published, [ 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. 
Arr. IV.—On American Amphibia ; by Anm. Sacer, M. D. 
Detroit, (Mich.) March 5, 1839. 
TO PROF. SILLIMAN, 
* Sir—tIr the following observations upon some of the Americatt 
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 
oH 
