No. 2.] MENTAL POWERS OF SPIDERS. 395 



August 15, 10 A.M. — Sounded the fork near the spider ten 

 times. She would not move. 5 P.M. — Made nineteen trials, 

 with the same result. 



August \6. — The fork was sounded twenty times in the 

 morning and twenty in the afternoon without disturbing her. 



August 17. — While the fork was sounded close to her eleven 

 times she stood immovable in the centre of the web. 



August 18. — The web was tenantless. Our little conica has 

 probably fallen a prey to some bird or wasp. 



As the habit of falling from the web is almost the only safe- 

 guard of these spiders in times of danger, the instinct must be 

 of immense importance to them. Taking this into considera- 

 tion, it seems remarkable that one of them should so soon have 

 learned the sound of the vibrating fork, and should have 

 modified her action accordingly. 



In all essentials our results agree with those of Mr. Boys, 

 who says : " If, when a spider has been enticed to the edge of 

 the web, the fork is withdrawn, and then gradually brought 

 near, the spider is aware of its presence and of its direction, 

 and reaches out as far as possible in the direction of the fork ; 

 but if a sounding-fork is gradually brought near a spider that 

 has not been disturbed, but which is waiting as usual in the 

 middle of the web, then, instead of reaching out toward the 

 fork, the spider instantly drops — at the end of a thread, of 

 course." ^ 



A few experiments were made to determine where the organ 

 of hearing is located, but we can offer nothing positive on this 

 question. It seems probable that the auditory apparatus is but 

 little specialized. Possibly it is spread over a considerable 

 portion of the epidermis. 



Finding that E. strix and E. lahyrinthea were very sensitive 

 to the tuning-fork, we removed both palpi from an individual 

 of each of these species. They seemed a good deal disturbed 

 by the operation, and retreated to the tents near their webs. On 

 the next day, when the fork was sounded near them, there 

 was no definite indication that it was heard. On the second 

 day they each responded once ; and on the third, they seemed 

 to have entirely recovered, and responded eight or ten times in 

 succession. We afterward removed the palpi from several 



' Loc. cit., p. 149. 



