PDF - Wallace Online

in PROTECTIVE RESEMBLANCES AMONG ANIMALS 53appear at first to be a source of danger to its possessor mayreally be a means of protection. Many showy and weakflyingbutterflies have a very broad expanse of wing, as in thebrilliant blue Morphos of Brazilian forests, and the largeEastern Papilios ; yet these groups are. tolerably plentiful.Now, specimens of these butterflies are often captured withpierced and broken wings, as if they had been seized by birdsfrom whom they had escaped ;but if the wings had beenmuch smaller in proportion to the body, it seems probablethat the insect would be more frequently struck or pierced ina vital part, and thus the increased expanse of the wings mayhave been indirectly beneficial.In other cases the capacity of increase in a species is sogreat that however many of the perfect insect may be destroyed,there is always ample means for the continuance ofthe race. Many of the flesh-flies, gnats, ants, palm-treeweevils, and locusts are in this category. The whole familyof Cetoniadse or rose chafers, so full of gaily-coloured species,are probably saved from attack by a combination of characters.They fly very rapidly with a zigzag or wavingcourse ; they hide themselves the moment they alight, eitherin the corolla of flowers, or in rotten wood, or in cracks andhollows of trees, and they are generally encased in a veryhard and polished coat of mail, which may render them unsatisfactoryfood to such birds as would be able to capturethem. The causes which lead to the development of colourhave been here able to act unchecked, and we see the resultin a large variety of the most gorgeously-coloured insects.Here, then, with our very imperfect knowledge of thelife-history of animals, we are able to see that there arewidely varied modes by which they may obtain protectionfrom their enemies or concealment from their prey. Some ofthese seem to be so complete and effectual as to answer all thewants of the race, and lead to the maintenance of the largestWhen this is the case, we can well under-possible population.stand that no further protection derived from a modificationof colour can be of the slightest use, and the most brillianthues may be developed without any prejudicial effect uponthe species. On some of the laws that determine the developmentof colour something may be said presently. It is