310 ASA A. SCHAEFFER 



water. A small strip of board was laid on the dish for the 

 frogs to sit on. In other parts of the cage were placed dead 

 leaves, grass and twigs. The cage was made as " homelike " 

 as possible. The frogs had ample opportunity to hide either 

 in the water or in the grass. Opportunity to hide is an ever 

 present feature in a wild frog's environment, and hiding places 

 should not be neglected when frogs are caged. The cage was 

 placed to the side of a south window which allowed a small 

 amount of sunlight each day. 



The frogs were kept under almost constant observation, as 

 far as their feeding is concerned, for four weeks before any of 

 the data in this paper were recorded. So much time was, how- 

 ever, not necessary for the frogs to accommodate themselves 

 to their unusual surroundings. All but R. virescens ate in a 

 normal manner in about four days after being placed in the cage ; 

 R. virescens was a shy frog and did not behave normally as 

 far as its feeding reactions are concerned until about two weeks 

 had passed. 



The {food of the frogs up to the time of the observations 

 on habit forming consisted of all manner of insects : house 

 flies; hornets; wasps, adults and larvae; ants; locusts, nymphs 

 and adults ; beetles ; bees ; cabbage butterflies (Pieris rapae) , 

 adults and larvae; bugs; leaf hoppers; and also earthworms, 

 centipedes, snails and sowbugs. Feeding was done at irregular 

 intervals, sometimes tw4ce a day and sometimes once in two 

 days. A sweep net was used to collect most of the food. No 

 new food was placed into the cage as long as living moving 

 food \\'as still there. The frogs seemed to be in very good 

 condition throughout the whole series of experiments. 



The first series of observations were yielded by what might 

 appropriately be termed the natural history method of experimen- 

 tation, since the reactions of the frogs were exactly such as 

 might be called forth any day of their lives in their normal 

 environment. The irregularity of the food supply may be 

 considered normal, for the quantity of available food in natural 

 conditions must be very variable and irregular, depending 

 as it does on temperature, humidity, light, etc. On the whole, 

 we may say that the frogs were subjected to no conditions 

 that might not befall them under normal circumstances. 



Inasmuch as it was possible that the food placed into the 



