36 Journal of Entomology and Zoology 
act as scavengers by greedily devouring all dead animal matter of the pond.’ For 
the bullfrog tadpole she says, “The mouth is well fitted to bite the delicate ends of 
leaves and stems, or to scrape off the tender green or brown plants from sticks and 
stones. It is equally adapted for eating animal food. The bullfrog tadpole (like 
that of the green-frog and that of the wood-frog), is especially fond of any animal 
food available. ‘Thus these tadpoles act as scavengers and dispose of dead fish or 
dead tadpoles even, that otherwise would become a menace to the living creatures 
of the pond.” 
Her remarks on the food of the adults bear out the statements made by other 
workers and show further that the bullfrog and the green-frog are the most aquatic 
of the eastern frogs, that the meadow- and pickerel-frogs are less so, while the 
wood-frog, peeper, tree-toad and common toad are even less inclined to be found 
in the water. The food is therefore expected to vary accordingly. 
Her observations on moulting the skin are also of interest. “The green-frog 
moults the skin four or more times each year. If the frog is out of the water when 
the moulting takes place, the process is like that of the American toad and of the 
leopard-frog, and the skin is swallowed. If the moulting takes place in the water 
the skin may float off in large patches and is not eaten.” 
From this short review of the literature in regard to the food of the Anura 
of this country, it can readily be seen that there are many statments as to the food 
of the adults and some remarks are even made as to that of the tadpole, but I 
have found nothing as to food during transformation, except that the tail is absorbed 
by phagocytic action and is used. It shall therefore be my attempt in the following 
pages to take up in more detail the food of the adult tadpoles, of the transforming 
ones, and of the young frogs. 
GENERAL DISCUSSION OF TRANSFORMATION 
One of the first evidences externally of transformation and the one most greatly 
affecting the food situation is the shedding of the horny plates characteristic of the 
tadpole’s mouth. After this takes place the alimentary canal decreases to one-tenth 
or one-twelfth of its larval length, and at the same time becomes differentiated into 
distinct portions. The larval digestive tube is merely a long tube, that of the young 
frog has a widened and thick muscular-walled stomach, a long narrow small intes- 
tine, and a much shorter but likewise thin-walled large intestine. In the specimens 
dissected the longest larval alimentary tract found in the bullfrog was 1070 mm., 
the average after decrease in length was from 85 to 95 mm.; for the green-frog the 
two measurements were 450 and 50 to 60 respectively, for the wood-frog 200 and 
18 to 20, for the pickerel-frog 400 and 30 to 35, for the meadow-frog 530 and 30 
to 40, for the peeper 88 and 10 to 15, for the tree-frog 170 and 15 to 18, and for the 
toad 110 and 10 to 15. While all this change is going on the mouth is gradually 
increasing in size to one many times larger than the tadpole mouth. Obviously while 
the mouth is still very small it is scarcely capable of taking in any food, its horny 
plates having been lost. In order that the materials eaten may be swallowed whole 
and not nibbled off, the mouth has to be considerably enlarged. It is not strange 
then, to find that without exception all eight species go through a period of fasting 
as far as taking food from the outside is concerned. An examination of the data 
