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given, it is not easy at first glance to distinguish the insect which is perched upon the twig

How successful these resemblances sometimes ray be in protecting the insect from its enemies, is well shown by an observation made by Mr. Belt, a capital English naturalist. On one occasion he saw a multitude of insect-eating ants run about and over the body of a large, leaf-like locust. As the latter remained perfectly still, the ants did not recognize it as being an insect at all, and so left it unharmed.1 A curious insect, a phasma, which Mr. Wallace found in Borneo,2 was so covered with olivegreen growths, that the native who showed it to him was sure that the insect really was covered with live moss.

It may be added that this insect greatly needs some such protection as that afforded by this curious resemblance; since it is very sluggish in its habits, and is greatly relished by insect-eating birds. In the wellknown cases of chameleons and tree-frogs, which change their color apparently at will, it is possible that two ends are subserved, — the protection of the animal from its enemies, and the facilitation of its unobserved approach to the

i Wallace's Tropical Nature, p. 93.

2 Ibid., pp. 92, 93,

[graphic]

Fig. 7. – Leaf-Butterfly, in flight and in repose.

flies and other insects upon which it feeds. Somewhat similar to these cases is that of a mantis, or praying-insect of Java, which is pink, and closely resembles a certain flower, an orchis, found in the same region. The advantage of this resemblance to the mantis will appear plain when it is stated that it lives upon butterflies, and that the whole group of plants to which the orchis belongs attracts butterflies and moths.1

Quite as curious as the cases of what have been called protective resemblances, such as those of the white hare, fishes, insects, and other animals, or as the sort of decoy resemblances, as they may be named, like that of the mantis, are the instances of what are known as warning-colors. Many South-American butterflies, belonging to two divisions, the Heliconidæ and the Danaida, are remarkable for the brilliancy of their coloring and for their slowness of flight. From these characteristics they form, as may be imagined, very conspicuous objects; and their numbers are not less remarkable than is their showiness. The secret of their numbers is plain, however, to the naturalist who captures one of these resplendent fellows; for all the species have a

! Wallace's Tropical Nature, p. 173.

most disgusting odor, which clings for a long time to any object that has touched one of them. It has been ascertained, that, probably for this reason, the insect-eating birds and lizards of the region where these butterflies are found refuse to have any thing to do with them. It is therefore an advantage to these uneatable species to be so differently colored from others, and so slow of flight as they are, since it thus becomes easy for the birds and lizards to recognize and avoid them. Another instance of the same kind occurs in the case of some of the Central-American tree-frogs, whose gorgeous coloring for a good while perplexed Mr. Belt. Some of these frogs had a brilliant red body and blue legs, while others were entirely of a bright blue color. But the mystery was solved, when the naturalist one day tossed one of these gaudy little frogs to a young and inexperienced duck, which at first picked it up, but instantly dropped it, apparently as much disgusted with the taste as it would have been pleased with that of an ordinary frog. Still another instance, perhaps, of the same sort of thing, is to be found, as Mr. Wallace reminds us, in the brilliant coloration of the uneatable sea-slugs and sea-anemones.

1 Tropical Nature, pp 175, 176.

2 Ibid., p. 189.

But the whole subject of warning-colors needs to be further studied; and it is likely, that, in very many instances, some useful object may be subserved by bright coloring. Not improbably the brilliancy of such insects as the beetle that feeds so abundantly on the leaves of dogbane, and the great rhinoceros-horned dungbeetle, so common in many parts of the country, serves to advertise these insects as uneatable.

Similar in purpose, possibly, to the warningcolors just described, are such striking appendages as the rattle of the rattlesnake, or the expanded neck of the cobra di capello, which may be explained, not as kindly warnings to the passer-by, that he may avoid the snake, and escape its fangs, but rather as a notice given by the snake on its own account, to show that it is a dangerous customer, and is better left alone. The flattened neck and head of the puff-adder, which is perfectly harmless, but looks, when it raises itself to strike, not a little like one of the poisonous snakes, is probably another case of mimicry for the sake of protection. So, too, there are tropical bugs which closely resemble wasps; while among our own insects

many

flies are found which look so much like bees or

1 A very poisonous snake, found in India, which flattens out its neck and bead like a hood, on being disturbed.

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