Pomona College, Claremont, California 55 
TABLE 11 
Percentage of Aquatic Forms Found in the Food of Adults as Compared with 
Newly Transformed. 
Bull- Green- Wood- Pickerel- Meadow- Tree 
frog frog frog frog frog Peeper toad Toad 
AQUHtic. Voc. ceric 25 .32 Seao is ia Jen 4 11 7 0 oO Le ett 0 10 
DOUDEE se aanlo rs « TSHR: % Te 2e -10 2 1 6 0 oy ie! 0 029 1 
Non-aquatic ..... 57 63 91 90 65 98 76 95 83 93 100 100 100 100 71 99 
In this table the figures express per cents, the one given first is for the young, the 
second being for adult. It will be at once apparent that the bull-frog is by far the 
most aquatic in feeding-habit, that the green-frog, although a form remaining close 
to the water, lives very largely on non-aquatic insects, that the peeper, tree-toad, 
and toad apparently eat practically no aquatic forms from the time that they 
transform, and that the wood-frog, pickerel-frog, and meadow-frog leave the water 
more gradually and always do have a small percentage of their food aquatic, 
although not so much of it is so in the adults as in the young. Of all these 
species the green-frog is perhaps the most surprising. Drake’s” results for the 
meadow-frog, based on the most exhaustive study yet made and showing a total of 
931 animals found in 209 stomachs, give about five per cent as being unquestionably 
aquatic, so that his work agrees very well with the results given above. 
Economic Bearing. 
The economic application of a piece of work of this sort should be two-fold. As 
new information is obtained regarding the food-habits of frogs, especially at trans- 
formation, their life-history and propagation can be better understood. If frogs are 
unable to eat at transformation, a fact which I think I have quite thoroughly estab- 
lished, it is useless to feed them at that time. The second point of application that 
comes to mind is that a study of the food of the newly transformed may show some- 
thing as to the usefulness of the species in destroying harmful insects, sow-bugs, slugs, 
and other forms. My data are hardly full enough nor important enough to go into 
this in detail, but a more extended investigation of the food of the adults is worth 
while from this standpoint. The results of other workers, such as Kirkland, Surface, 
and Drake, do show that a great many harmful forms are destroyed. For more detail 
their writings should be consulted. 
Conclusions and Summary. 
Eight species of Anura were studied during their transformation to learn some- 
thing of their food-habits as larve, as transforming individuals, and as young frogs 
or toads. The species studied were as follows: 1 
Rana catesbeiana Shaw. The Bull-frog. 
Rana clamitans Latreille. The Green-frog. 
Rana sylvatica Le Conte. The Wood-frog. 
Rana palustris Le Conte. The Pickerel-frog. 
Rana pipiens Schreber. The Leopard- or Meadow-frog. 
Hyla crucifer Wied. The Peeper. 
Hyla versicolor Le Conte. The Tree-toad. 
Bufo americanus Holbrook. The Common Toad. 
Drake, C. J., 1914. The food of Rana pipiens Shreber. Ohio Naturalist, 14:257-269. 
