Page:The Zoologist, 4th series, vol 3 (1899).djvu/476

446 peds. Ajuga chamæpitys is a mimic of Euphorbia cyparissias, with which it often grows, and which is protected by its acrid juice. The most familiar case, however, is that of the Stinging and the Dead Nettles. They very generally grow together, and, though belonging to quite different families, are so similar that they are constantly mistaken for one another. But even here caution is necessary in many cases before giving a verdict for mimicry as generally understood. Zopf (1892), in studying the colouring-matter of the fungus Pilobolus, found that a parasite growing on the fungus took up not only the drops of oil, but also the pigment associated with the oil, the result being that parasite and host were similarly coloured. Poulton has also shown that the green pigment of some caterpillars is derived from the green leaves upon which they live.

It is to be remembered, however, as Mr. Ridley has remarked, that it is not essential that fruits should be flavoured to our taste in order to induce birds or animals to swallow them. In the Malay Peninsula "the Macaranga capsules, covered with a viscid gum most unpleasant to the mouth, the hot Capsicums, the drupes of the palms (Kentia macarthuri), the berries of the wild grapes (Cissus spp.), which have a most irritating effect on the mouth, and the poisonous fruits of Sapium, are all highly popular with birds, and even the fruit of Strychnos tieute, Bl., with its intensely bitter pulp, is eaten by Civet Cats. A large number of the wild fruits, too, though very astringent, are sometimes eaten by birds or animals." In the North-West Provinces of India, Mr. Silberrard has known Goats to "frequently eat, without any ill-effect, the leaves and green stems of the 'Akaúa' or 'Madar' (Asclepias or Calotropis gigantea), the milky juice of which is an acrid poison for human beings, and is frequently used as such in infanticide cases."

We do not suggest, or in any sense imply, that the few and scanty instances we have given of "Demonstrated Mimicry" are at all commensurate with the much larger number that could be