HABIT FORMATION IN FROGS 313 



evidently not been quite sufficient to establish a habit lasting 

 longer than one day. 



Rana damata (small) snapped up a caterpillar after it had 

 dropped from the ceiling, and swallowed it with great difhculty. 

 No visible attempt was made to reject it. 



July 31. — I placed an adult locust (Dissosteira Carolina) 

 into the cage. Rapm damata (small) became interested after 

 the locust had been in the cage a few minutes. When the 

 locust had climbed up the side of the cage about 22 cm. above 

 the floor, the frog jumped, but struck the side of the cage 3 cm. 

 below the locust. 



Rana damata (medium) also became interested a few minutes 

 after the small spring frog had jumped at the locust. The 

 locust was climbing up the side of the cage, and when about 

 12 cm. above (vertically) and 7 cm. away (horizontally) the 

 frog jumped, landing against the side of the cage below the 

 locust. A few minutes later I induced the locust to climb up 

 the side of the cage at another point. When it was about 

 10 cm. above the frog, the frog straightened up, and after ex- 

 amining the locust for about 30 seconds, moved back a little 

 and squatted down. The locust was all the time slowly climbing, 

 and always within reach of the frog. 



It would have been impossible for the small R. damata to 

 eat the locust, and it would have been very difficult for R. damata 

 (medium) to eat it; we may infer therefore that the size of the 

 object was responsible for the peculiar behavior on the part 

 of both frogs. I noticed, both before and after this observation, 

 that when frogs jump for small locusts, flies, etc., they land 

 almost exactly at the spot on which the locust or fly is located. 

 The large size of the locust seems therefore to have partially 

 inhibited the feeding reaction. This inhibitory action plus 

 the effect of the previous unsatisfactory jump at the locust 

 resulted for R. damata (medium) in almost complete inhibition 

 of reaction. At the conclusion of the experiment the locust 

 was removed from the cage. 



August I, 10 A. M. — The locust was again placed into the cage. 

 Rana damata (medium) became interested the moment the 

 locust began climbing up the wall of the cage. In about a 

 minute the frog, striking below the locust, brought it down 

 with only its left hind foot in the frog's mouth. The locust 



