Article beginning on page 299.
Psyche 3:299, 1880.

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WHILE in Switzerland, in September
1880, I noticcda peculiar kiwi of defen- yive inimicrv on the part of an uiideter- mined species of pJwhingidae. which I
have nowhere seen recorded. In ap-
proaching a rocky lodge op 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, lint which I found, on ncariug the ledge, to be a great num- her of 'pJffslofMidw, or LLharvest-~eii." On corning near the place where the?
were, each of them began a rather rapid
dorso-ventral motion of the body, swiug- iug it backward and forward on their
legs. As the rock on which. they rested
was nearly perpendicular, and their eight outspread, long. and slender tegs rested on the projuctions of the irregular rocky siirface, allowing tbcir 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 ol'ten observed, some species
of spiders, when disturbed, swing their
web rapidly hack and forth, while cling- ing at its centre. The motion of the
body, in the species of phula?t~jidae that I observed, was of un impulsive, jerking nature, like the motion of the spiders
just mentioned, when similarly disturbed. At each sudden movement of my hand
ii large part of the phalanqi&ie, with
which the rock was dotted to the uum-
her of thousands, would rac-ommeuce
the motion described above. but none of
DEFENSIVE MIMICRY IN PHALANGIDAB.
BY (iEOJIGE DIMMOCK, CAMBRIDGE, MASS.
them ran awa~+ until they were tonchcd,
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-tastiug
than y!wh~iyidae themselves,* and that
the p7~uictn~idw, by imitation, avoid be- ing eaten by birds? Or is it, on the
contrary, the spiders which, for their
owe protection, imitate the phalaqirhe?
That the motion described above origina- ted with the spider and. later served the phalmgidiie for protection seems to me
more probable, for the spider has, to all appearances, another and a more natural
purpose in shaking his web.
A8 a eai-
tor on deck shakes and yanks his ropes
to see if they are firmly fastened and
free from encumbrances, so the spider
shnkce his web from his central resting
place to determine if each fastening is
in proper order, or if an insect has tan- gled itself in any part of hia web.
The
phvlangidae would easily deceive birds by this motion, which, otherwise, for them, seems to have no explainable purpose.
Although I had of ten swv single spec-
linens of pltda+qidtte 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. Fravsm, J Dec. 1881.
* hhnv species ofjkahzg;dtie pour out nsecretion when disturbed, which is sufficiently dis reeable, in
smell and tiiste, to (is.; but, as taste* aiidrtistastes in man and birds dn not always aqrec, this ~ticrctioii may not tie a protection from tlic attacks of certain birris.



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