INSECTS INJURIOUS TO THE POTATO. 91 
which T. sericodon was first discovered by Dr. H. C. Wood 
in Southern New Jersey, and T. sicaria by Philip T. Tyson 
in Southern Maryland. In both localities their remains are 
mingled with those of Dolphins and Whales, and their car- 
cases have all floated together on the ocean currents and tides 
to their present resting places. In Europe there are some 
species of the same genus, while allies of the true crocodilian 
form represent the Plerodon of Meyer. The gavials of the 
Cretaceous present a similar character of teeth, sd approach 
remarkably near to the Thecachampse, when we consider 
the great hiatus between the life of the two great periods in 
other departments. The gavials of the Miocene differ in but 
a few important points from the Thoracosauri of the Creta- 
ceous. The latter were very numerous in — and 
appear under five specific forms. 
In the plate accompanying this article, the artist has 
attempted an ideal representation of a few of the subjects 
which haunted the shores of our country, when our prairies 
were the ocean bottom, and our southern and eastern borders 
were far beneath the Atlantic. Zelaps aquilunguis occupies 
the foreground on a promontory, where his progress is inter- 
rupted by the earnest protest of an Elasmosaurus. Mosasau- 
Tus watches at a distance with much curiosity and little good 
will, while Osteopygis views at a safe distance the unwonted 
Spectacle. On the distant shore a pair of the huge Hadro- 
sauri browse on the vegetation, squatting on their haunches 
and limbs as on a tripod. Thoracosaurus crawls up the banks 
with a fish, and is ready to disappear in the thicket. 

INSECTS INJURIOUS TO THE POTATO. 
BY HENRY SHIMER, M. D. 
Or the several distinet species of potato bugs, the Colo- 
rado ite pen 10-lineata Say, Fig. 13; a, eggs; b, 


