LOCOMOTIONS OF SURFACE -FEEDING CATERPILLARS. 14! 



unhesitating manner in which it continues up and up is enough 

 to rejoice any stanch believer in negative geotropism as the 

 guiding power. Frequently pausing to make exploring move- 

 ments, 1 it encircles the top a couple of times and then descends 

 to h. It moves along h to its tip, makes exploring movements, 

 returns to the post, descends to e, pausing several times to make 

 exploring movements. It passes along e to /, makes exploring 

 movements, descends/ to its tip and makes exploring movements 

 towards c. It reascends/ to e, makes exploring movements, and 

 returns to the tip of/. It makes exploring movements and then 

 moves across the gap to c. It moves along c to b, along b to a 

 and down a to the post. After making exploring movements, it 

 encircles the post halfway, descends to the ground, moves off 

 about three feet and rests indefinitely. 



In this experiment, the subject of which is a tent-caterpillar, 

 the arms j, g, h extend obliquely upward, on the left side of the 

 post, at an angle of thirty degrees ; d extends horizontally to the 

 right; e, almost vertically upward, and /, almost horizontally 

 back to the post; a extends obliquely upwards toward the left, 

 at an angle of thirty degrees; b, horizontally towards the left; 

 and c, obliquely upward, at an angle of about thirty degrees. 



Following a path which is sometimes straight and sometimes 

 spiral, the caterpillar continues upward until it reaches g, which 

 it ascends to the tip. There it spends several minutes making 

 exploring movements; then descends g to the post and crawls 

 up it to the top. It goes about half way around the circumfer- 

 ence, then crosses over to the opposite side and descends the 

 post. Pausing occasionally to make exploring movements, it 

 continues downward to h. It ascends h to its tip, crosses over 

 to the opposite side and returns to the post. It continues down- 

 ward an inch, rests a few minutes. Occasionally pausing to make 

 exploring movements, it continues spirally downward to g, which 

 it ascends for about four inches and upon which it rests quietly 

 a few minutes. Returning to the post, it continues downward 



1 When a caterpillar reaches the end of branch or twig, when it encounters an 

 angle or an obstacle, and sometimes for no visible reason, it pauses, elevates the 

 front portion of its body, stretches it forward and upward (sometimes slightly 

 downward) and waves it with a wabbly movement. For the sake of terseness in 

 descriptions, this form of behavior has been called "exploring movements." 



