654 General Notes. 
ENTOMOLOGY: 
SOME OBSERVATIONS ON THE MENTAL POWERS OF SPIDERS.— 
Under this title an important memoire is published by George W. 
and Elizabeth G. Peckham,’ in which these observers detail numer- 
ous experiments upon the senses and mental powers of spiders. The 
following extracts will serve to indicate the scope of these experi- 
ments, and some of the conclusions deduced from them. 
“Our experiments on the senses of smell in spiders extended over 
two summers. Many of them were performed by each of us sepa- 
rately, that we might detect the mistakes of the other. Our usual 
plan was to hold a slender glass rod, eight inches in length, in such 
a position that one end closely approached the spider, noting what 
effect, if any, was produced, and then to dip it into whatever scent 
we were using, hold it in the same position, and again note the 
effect. We tested them in this way while at rest in the web, while 
stalking their prey, while feigning death, and under various other 
conditions. ; 
“The scents used were essential oils, cologne, and seteral kinds 
of perfumes. Acetic acid, vinegar, and like materials were avoided 
on account of their irritating action upon the integument. 
o sum up our work on the sense of smell, we made, in all, 
two hundred and twenty experiments. We found three species 
(Argyroepeira hortorum, Dolomedes tenebrosus, and Herpyllus eccle- 
siasticus) that did not respond to the tests. In all other cases 1t was 
evident that the scent was perceived by the spiders. This they 
showed in different ways,—by various movements of the legs, palpi 
and abdomen, by shaking their webs, by running away, by seizing 
the rod and binding it up with web as they would an insect, and in 
case of the Attidæ, by approaching the rod with the first legs and 
palpi held erect; but whether in the way of attacking 1t, or, as It 
sometimes seemed, because the smell was pleasant to them, 1t 18 
impossible to say.” : 
e most successful experiments upon the sense of hearing were 
conducted with tuning-forks. “These show that certain spiders 
indicate that they hear a vibrating tuning-fork by characteristic 
movements of the legs. Another set of spiders, however, mani- — 
fest their perception of the sound in a different way. With th 
! This de } ornell Univer- 
Best nem N. Yo ré edited by Prof. J. H. Comstock, © ite, 
whom communications, books for notice, , 
should be sen 
2 Journal of Morphology, Vol. I., No. 2, pp. 383-419; also published 
separately by Ginn & Co., Boston. 
