pplicable to-day: "Many of the
Germans are very contemptuous about making out use of organs; but they
may sneer the souls out of their bodies, and I for one shall think it
the most interesting part of natural history." ("More Letters" II. page
428.)

PROTECTIVE AND AGGRESSIVE RESEMBLANCE: PROCRYPTIC AND ANTICRYPTIC
COLOURING.

Colouring for the purpose of concealment is sometimes included under the
head Mimicry, a classification adopted by H.W. Bates in his classical
paper. Such an arrangement is inconvenient, and I have followed Wallace
in keeping the two categories distinct.

The visible colours of animals are far more commonly adapted for
Protective Resemblance than for any other purpose. The concealment of
animals by their colours, shapes and attitudes, must have been well
known from the period at which human beings first began to take an
intelligent interest in Nature. An interesting early record is that of
Samuel Felton, who (Dec. 2, 1763) figured and gave some account of an
Acridian (Phyllotettix) from Jamaica. Of this insect he says "THE THORAX
is like a leaf that is raised perpendicularly from the body." ("Phil.
Trans. Roy. Soc." Vol. LIV. Tab. VI. page 55.)

Both Protective and Aggressive Resemblances were appreciated and clearly
explained by Erasmus Darwin in 1794: "The colours of many animals seem
adapted to their purposes of concealing themselves either to avoid
danger, or to spring upon their prey." ("Zoonomia", Vol. I. page 509,
London, 1794.)

Protective Resemblance of a very marked and beautiful kind is found
in certain plants, inhabitants of desert areas. Examples observed by
Burchell almost exactly a hundred years ago have already been mentioned.
In addition to the resemblance to stones Burchell observed, although
he did not publish the fact, a South African plant concealed by its
likeness to the dung of birds. (Sir William Thiselton-Dyer has suggested
the same method of concealment ("Annals of Botany", Vol. XX. page 123).
Referring to Anacampseros papyracea, figured on plate IX., the author
says of its adaptive resemblance: "At the risk of suggesting one perhaps
somewhat far-fetched, I must confess that the aspect of the plant always
calls to my mind the dejecta of some bird, and the more so owing to the
whitening of the branches towards the tips" (loc. cit. page 126). The
student of insects, who is so familiar with this very form of protective
resemblance in larvae, and even perfect insects, w