PSYCHE. 
DEFENSIVE 
BY GEORGE 
Waite in Switzerland, in September 
1880, I noticed a peculiar kind of defen- 
sive mimicry on the part of an undeter- 
mined species of phalangidae, which I 
have nowhere seen recorded. In ap- 
proaching a rocky ledge on the road be- 
tween St. Gingolph and Novel, near the 
south side of Lake Geneva, my attention 
was attracted by what I at first supposed 
to be a large number of small webs with 
large spiders in them, but which I found, 
on nearing the ledge, to be a great num- 
ber of phalangidae, or ‘*harvest-men.” 
On coming near the place where they 
were, each of them began a rather rapid 
dorso-ventral motion of the body, swing- 
ing it backward and forward on their 
legs. As the rock on which they rested 
was nearly perpendicular, and their eight 
outspread, long, and slender legs rested 
on the projections of the irregular rocky 
surface, allowing their bodies to swing 
in the cavities between these projections, 
each of them resembled very closely, 
viewed from a short distance, a small 
geometric web containing a spider, for, 
as I have often observed, some species 
of spiders, when disturbed, swing their 
web rapidly back and forth, while cling- 
ing at its centre. The motion of the 
body, in the species of phalangidae that 
I observed, was of an impulsive, jerking 
nature, like the motion of the spiders 
just mentioned, when similarly disturbed. 
At each sudden movement of my hand 
a large part of the phalangidae, with 
which the rock was dotted to the num- 
ber of thousands. would recommence 
the motion described above, but none of 
MIMICRY IN 
DIMMOCK, 
299 
PHALANGIDAEZ. 
CAMBRIDGE, MASS. 
them ran away until they were touched, 
seeming to trust in the efficacy of their 
mode of imitative defense. 
Can it be that the spiders which cause 
the before-mentioned swinging of their 
web when disturbed are more ill-tasting 
than phalangidae themselves,* and that 
the phalangidae, by imitation, avoid be- 
ing eaten by birds? Or is it, on the 
contrary, the spiders which, for their 
own protection, imitate the phalangidae ? 
That the motion described above origina- 
ted with the spider and later served the 
phalangidae for protection seems to me 
more probable, for the spider has, to all 
appearances, another and a more natural 
purpose in shaking his web. Asa sai- 
lor on deck shakes and yanks his ropes 
to see if they are firmly fastened and 
free from encumbrances, so the spider 
shakes his web from his central resting 
place to determine if each fastening is 
in proper order, or if an insect has tan- 
led itself in any part of hisweb. The 
phalangidae would easily deceive birds by 
this motion, which, otherwise, for them, 
seems to have no explainable purpose. 
Although I had often seen single spec- 
imens of phalangidae going though the 
same motions on horizontal surfaces, 
even while they. were walking, it was 
left to this great multitude of specimens, 
hanging on a jagged ledge, to suggest. 
by actually deceiving me at first sight, 
the probable object of this strange mo- 
tion. Paris, France, 3 Dec. 1881. 
* Many species of phalangidae pour out a secretion 
when disturbed, which is sufficiently disagreeable, in 
smell and taste, to us; but, as tastes and distastes in 
man and birds do not always agree, this secretion may 
not be a protection from the attacks of certain birds. 
