316 ASA A. SCHAEFFER 



pillar then crawled away without eliciting immediately any 

 further response from the frog. The caterpillar kept on crawling 

 to the end of the board and up the side of the cage. When 

 it came to the ceiling, it lost its foothold and dropped into 

 the water close beside the board on which the frog sat. The 

 wriggling of the caterpillar as it lay on the surface of the water 

 attracted the frog's attention. A short hop oriented the frog. 

 After watching the caterpillar for about lo seconds, the frog, 

 with a very short hop, resumed its original position with the 

 body axis at right angles to the direction in which the cater- 

 pillar was located. 



On July 29 this frogf ormed the habit, in two trials, of avoid- 

 ing crawling hairy caterpillars. It is probable that no hairy cater- 

 pillars were tried again till 9.30 August 9. The effects of the habit 

 were not wholly lost, as might at first sight appear, when the 

 caterpillar was snapped up on August 9, for it took only a single 

 trial to perfect the habit again. It is also possible that the 

 unusual state of hunger was partly responsible for the break 

 in the habit. But, interpreting the facts as they stand, it can- 

 not be denied that the habit of avoiding hairy catei*pillars 

 persisted to some extent for 10 days. 



August 13, 5.30 p. M. — Since August 9 the frogs had been 

 very scantily fed. I now put another caterpillar into the cage. 



Rana clamata (medium) manifested interest in the cater- 

 pillar 5 seconds after introduction. Two very short hops brought 

 the frog within 3 cm. of the caterpillar. The frog then bent 

 down the head and examined the caterpillar for about 40 seconds. 

 At the end of this period the frog jumped away 5 cm. to the 

 right with the body axis at right angles to the position occupied 

 while examining the caterpillar. During the next 30 minutes 

 the frog did not respond visibly to the movements of the cater- 

 pillar. 



Rana sylvatica took no notice whatever of the caterpillar. 



Rana virescens hopped toward the caterjDillar and then snapped 

 it up, but immediately released it in the usual way. The frog 

 took no further notice of the caterjDillar. 



Rana clamata (small) sat in the dish while the previously 

 recorded behavior was observed. When the caterpillar w^as 

 crawling again unmolested, near the dish, the frog hopped 

 out of it, snapped up the caterpillar, but immediately released 



