1911.] NATURAL SCIENCES OF PHILADELPHIA. 405 



•degree of sensitiveness to odors, but they seemed to respond slightly 

 quicker than do the females. Perhaps this is due not to the higher 

 development of their olfactory organs, but to their greater activity. 

 Probably the same reason is sufficient to explain the quicker response 

 to odors of Phidippus than of the Lycosas. Only a few experiments 

 were conducted with spiderlings. In these few cases their actions 

 were not essentially different from those of the adults. Females about 

 ready to oviposite were generally very slow to respond and in a few 

 •cases were almost negative to odors. A few hours before and after 

 moulting specimens were entirely negative to odors. On the first 

 day a female of Trochosa frondicola (Emert.) responded rather slowly; 

 on the fifth day she was almost negative; on the sixth day a large 

 insect parasite was removed from her abdomen. After this she lived 

 two months but never again responded readily to odors. Other 

 individuals of her kind also responded very slowly. Ten individuals 

 •of Ariadna bicolor likewise responded very slowly; when not in their 

 tubes their average time was 63 seconds for the five oils, and when in 

 their tubes they rarely responded to any kind of odors. A female 

 •of Dysdera interrita which did not spin any kind of a nest responded 

 .still more slowly; the average time for the five oils was 70 seconds. 

 Generally on damp or rainy days all specimens responded very slowly 

 and since no definite conclusions could be derived by including such 

 data, all results on these days have been eliminated. If the individuals 

 were normal in every way they may be educated to respond to odors 

 more quickly each successive day. In twenty-three specimens of 

 L. lepida the time for the first day was 14 seconds, for the second day 

 12 seconds, thus making an increase of fourteen per cent. 



(b) Hearing. 



In order to determine whether spiders show any response to sounds 

 which a person may hear any day in the same environs in which 

 arachnids live, I placed five male crickets, two small and one large 

 katydid beneath the experimental cases. The pitch of all the cricket 

 chirps were very similar, but the notes of the small katydids were 

 rather high, while those of the large katydid were pretty low. For 

 over a week's time I watched the spiders every day very carefully, 

 but not once did I ever notice a single spider show the least response. 

 I observed very closely the first time the insects were brought into the 

 laboratory, and in order to test them repeatedly the music makers 

 were removed from the room, then were brought back after a short time, 

 but in every case the result was a negative one. Also it was noticed 

 that there was no response whatever whether the araneads were quiet, 



