rotection.

Here, then, I think we see reasons, for many at any rate, of the
variations of color and markings in caterpillars, which at first sight
seem so fantastic and inexplicable. I should, however, produce an
impression very different from that which I wish to convey, were I to
lead you to suppose that all these varieties have been explained, or
are understood. Far from it; they still offer a large field for study;
nevertheless, I venture to think the evidence now brought forward,
however imperfectly, is at least sufficient to justify the conclusion
that there is not a hair or a line, not a spot or a color, for which
there is not a reason--which has not a purpose or a meaning in the
economy of nature.

[Illustration]

PROTECTIVE RESEMBLANCES IN SPIDERS

BY ELIZABETH G. PECKHAM.[10]

[10] Abbreviated from the occasional Papers of the Natural History
Society of Wisconsin, Vol. I., 1889. By permission.

[Illustration]

There are, among spiders, two forms of protective modification: the
first, including all cases of protective resemblance to vegetable and
inorganic things--that is, all modifications of color or of color and
form that tend to make them inconspicuous in their natural
relations--I shall call direct protection. The second form, which I
shall call indirect protection, includes two classes, the spiders
which are specially protected themselves and those which mimic other
creatures which are specially protected.

Spiders are specially protected when they become inedible through the
acquisition of hard plates and sharp spines. The modification of form
is frequently accompanied by conspicuous colors, which warn their
enemies that they belong to an unpalatable class.

The second class of indirectly protected spiders--those that mimic
specially protected creatures--presents some difficulties, since it is
not always easy to determine whether the purpose of mimicry is
protection or the capture of prey. The resemblance may, as is
frequently the case in direct protection, serve both purposes.

In looking for instances of protective form and color among spiders we
encounter one difficulty at the outset. The meaning of a protective
peculiarity can be determined only when the animal is seen in its
natural home. The number of strangely modified forms depicted in
descriptive works on spiders is enormous. Bodies are twisted,
elongated, inflated, flattened, truncated, covered with tubercles or
spines, e