314 ASA A. SCHAEFFER 



freed itself easily- The frog made no further attempts to get 

 it, nor was there any visible reaction to it for over an hour, 

 although the locust was nearly ah\'ays within easy striking 

 distance. 



Rana sylvatica was not observed to react visibly to a locust 

 of such size, although it is just barely possible that the frog could 

 swallow it. 



August I, 3 p. M. — I again placed the locust into the cage. 

 There was no visible response on the part of any of the frogs. 

 Nor was there any response to the hairy caterpillars which 

 have been in the cage continuously since July 29. When I 

 removed the caterpillars I found that none had been eaten 

 except as recorded above. 



August 9, 9.30 A. M. — The frogs have not been fed for two 

 days. I placed one of the hairy caterpillars into the cage. 

 Each of the four frogs in turn snapped up the caterpillar, but 

 in every case extruded the tongue subsequently and shook the 

 caterpillar off. Then the caterpillar was taken out of the cage. 



August 9, 12.30 p. M. — The caterpillar was placed into the 

 cage again. 



Rana sylvatica reacted first by making two short hops to 

 orient so as to look directly at the caterpillar. (The caterpillar 

 was about 5 cm. in front of the frog). The head of the frog 

 was then slowly lowered and brought forward toward the cater- 

 pillar, but I could not see that the tongue was shot out although 

 I watched especially to see if this would happen. In a second 

 or two the head lurched forward a little more and then the 

 tongue was very slowly extended, barely touching the cater- 

 pillar. The tongue was now withdrawn and then suddenly 

 extruded, with what appeared as a very slight attempt to shake 

 the caterpillar oft'. The caterpillar elicited no further response 

 during the next 45 minutes. 



Rana clamata (small) and R. virescens paid no attention 

 whatever to the caterpillar. 



Rana clamata (medium) reacted visibly when the caterpillar 

 was 10 cm. in front of it. See figure i. The interval between 

 the moment when I dropped the caterpillar in front of the frog 

 and the initial reaction was about 2 seconds. The caterpillar 

 w^as dropped on the edge of the board lying on the dish of water. 

 The moment the caterpillar started crawling along the board 



