312 ASA A. SCHAEFFER 



methylene blue powder. These colored caterpillars were then 

 placed into the frog cage where they crawled around in normal 

 fashion. Although they crawled in the most tempting positions 

 for over an hour, not any of the frogs manifested any visible 

 response. The very marked difference in coloring of these 

 caterpillars was inGufhcient apparently to cause a break in the 

 rapidly foiTned habit of avoiding hairy caterpillars. The color 

 of the caterpillars evidently had little or nothing to do in the 

 formation of the habit in this case. 



July 30, 4 p. M. — The caterpillars when disturbed spin a thread 

 of silk and suspend themselves on it until the disturbance is 

 over, when they crawl back again to their original position. 

 A normal caterpillar was observed to suspend itself in this 

 manner about 5 cm. in front of the wood frog and about 3 cm. 

 from the bottom of the cage. The caterpillar wriggled, and 

 was snapped by the frog almost immediately. The caterpillar was 

 held in the mouth for a half-second. The tongue was then 

 thrown out and held out for two or three seconds. The cater- 

 pillar, however, stuck fast, and when the tongue was mthdrawn 

 into the mouth the caterpillar went with it. It was soon 

 swallowed with seeming difficulty. The wood frog did not 

 later react toward any of the crawling caterpillars. 



The eating of this caterjoillar does not indicate a dissolution 

 of the recently foiTned habit of refusing this kind of organism. 

 The stimuli from a wriggling suspended caterpillar are quite 

 different from those of a crawling caterpillar. The stimuli 

 from the crawling cater[:»illar were probably the only ones upon 

 which the avoiding habit was based. (We have noted that 

 color played little or no part in this case.) When these stimuli 

 were absent, the previousl}^ formed habit of course could not 

 operate. 



Rana virescens. The caterpillars collect on the ceiling of 

 the cage and then remain quiet if left to themselves for a few 

 hours. It thus happened that the frog had not seen any crawling 

 caterpillars for four and a half hours. When I placed a cater- 

 pillar on the rim of the berry dish in which the frog was sitting, 

 the caterpillar was snapped up at once, but the tongue was 

 quickly thrown out, and the frog being in the water, the caterpillar 

 was washed off. This frog could not be induced to react toward 

 another caterpillar. The three trials on the previous day had 



