BEHAVIOR OF SPIDERS AND OTHER INSECTS 423 



to establish the habit in animals from which both antennae have 

 been amputated. 



Turner (97) experimented with adult roaches of both sexes, 

 larvae of several diffeient ages, and roaches from which the 

 antennae had been amputated. This investigator agrees with 

 the conclusions reported in the above paragiaph and adds: 

 " Generally speaking, male roaches learn more rapidly than 

 female and young roaches aie more apt than adults, but there 

 are marked individual exceptions to this; roaches that have 

 acquired the habit of refusing to enter a specific dark place 

 do not lose that habit when they moult; during sickness and 

 just prior to death, the retentiveness of the roach is much im- 

 paired." To test the meaning of this refusal to enter the dark 

 chamber, Turner conducted the following experiment. A bot- 

 tomless pen, containing one dark and one lighted chamber, was 

 placed on a piece of white cardboard. A roach that had thor- 

 oughly learned to avoid the dark chamber and which had just 

 been tested to see if the habit was well fixed, was placed in the 

 lighted compartment of this pen. As soon as its meanderings 

 brought it to the entrance of the dark room, it would enter. 

 Immediately the roach was returned to the lighted compart- 

 ment of the pen which was resting on the shocking board. In 

 that pen it could not be induced, even by gently shoving it, to 

 enter the dark section. Alter many repetitions of this experi- 

 ment had demonstrated that normal roaches almost invariably 

 react in this manner, the investigator concluded: "To my mind 

 this test is a conclusive proof that the change in behavior of 

 these insects is not due to a physiological reversal of the photo- 

 tropic responses of the roaches, but a case of learning, by ex- 

 perience, to avoid a specific dark place because of certain dis- 

 agreeable experiences connected with it." 



By means of experiments, Wodsedalek (108) has been able to 

 induce may-fly nymphs to form three new kinds of associations : 

 (1) they weie induced to increase the distance they would 

 swim towards a stone, even when they must swim against the 

 rays of light; (2) by means of rough handling, they were caused 

 to exhibit fear (these fear reactions are discussed under " Emo- 

 tions."), and, (3) by a method about to be described, they were 

 trained to make new responses to food. Bits of algae were 



