OLFACTORY REACTIONS IN AMPHIBIANS 619 



other insects. Hodge ('98) refers to the large numbers of house- 

 flies eaten by the toad. Schaeffer ('11) mentions the variety of 

 insect food taken by frogs in confinement. Quaintance and 

 Brues ('05) show how toads make use of very diverse forms of 

 insects as food. Slonaker ('00) and others have fed meat to toads, 

 by simulating the motion of small insects to attract attention. 

 The behavior of toads and frogs in confinement leads to the 

 inference that food ordinarily must be in a living condition and 

 in motion to be attractive. 



Among food materials taken by the toad under normal cir- 

 cumstances there are many insects with characteristic odors. 

 Conradi ('01) infers that the odor of the cucumber beetle 

 (Anasa tristis) is inimical to the toad, but Hill ('73) observed 

 no disastrous results to toads that had fed on this insect. Neither 

 frogs nor toads hesitate to make use of other vertebrates as 

 food, when occasion offers, or to devour members of their own 

 species. Can it be shown that these animals are stimulated to 

 seek for food or refuse it because of odors? With this question 

 in mind the following feeding experiments were carried on with 

 the toad (Bufo americanus LeConte). 



2. Materials and methods 



The toads used in these experiments were obtained in the 

 vicinity of Cambridge, Massachusetts, quite late in the year. 

 They were kept in a large box containing soil and leafmold in 

 a moderately cool basement room. The soil was kept damp and 

 the box dark. Some of the animals buried themselves in the 

 soil, others took shelter under bits of wood. The animals 

 reacted normally in all respects, taking food when offered. 

 The food consisted mainly of mealworm larvae (Tenebrio 

 molitor), of earthworms and dungworms (Allolobophora foe- 

 tida), flies and other insects. Some of the toads were removed 

 to large jars for greater convenience. Not all the animals 

 were ahke, some showing a greater tendency to hibernate 

 than others. Food was generally given the toads at intervals 

 of several days, but this procedure was modified as necessary. 

 For convenience the experiments were carried on with the 



THE JOUR^fA^ OF EXPERIMENTAL ZOOLOGY, VOL. 16, NO. 4 



