Genuine cases of mimicry are not so easily shown to exist among plants. The resemblance between white dead nettle (Lamium album) and the stinging nettle, as well as between other labiates and the stinging nettle, may be considered to be a case of real mimicry as defined above. The true stinging nettles are avoided by animals, owing to their possession of stinging hairs, which contain an acid fluid capable of causing pain and producing blisters. It would be clearly of advantage to another plant to resemble one possessing such defensive armor as the stinging nettle. There is another labiate, Ajuga ophrydis of South Africa, mentioned by Mr. Mansel Weale. This labiate closely resembles an orchid, and for this reason insects may be induced to visit the flower and thus fertilize it. Mr. Worthington Smith, the eminent fungologist, has found three rare British fungi, each accompanying common species, which they closely resembled; and one of the common species has a bitter nauseous taste. In this case we have an example of genuine mimicry. Dr. Hans Meyer has given in his valuable work, _Across East African Glaciers_, some very striking instances of mimicry. He says: “The similarity for the purpose of protection of the majority of the great mammals, _i. e._, the likeness of the color of their coats, and partly also of their external appearance, to the features and colors of the regions which they inhabit, must strike every traveler with astonishment. “At a small distance the hartbeest (antelope), when stationary, is really not distinguishable from red ant-heaps which everywhere abound; the long-legged and long-necked giraffe can not be distinguished from the dead trunk of a mimosa, the zebra from a gray-brown clump of grass and thorn-scrub, the rhinoceros from a fallen trunk of a tree. It is only when they move that they can be distinguished. Nature has also extended this protective mimicry (Schutzspiel) to the small insects; and perhaps for this reason they often escape the eye specially in search of them; for butterflies and grasshoppers look like dry twigs, the cicadæ like leaf-stalks, the spiders like thorns, the phasmodæ like bare twigs, beetles like small lumps of earth and small stones, moths like mosses and lichens. “This protective mimicry is manifested not only in regard to the colors and forms of the animals, but also as regards their movements, or their manner of standing still, and in their preference for certain localities appropriate to their disguise. There is protection everywhere; protection against climatic extremes and against animal foes; such varied and abundant protection as could only be developed by natural selection in a primeval continent like Africa.”