Page:Popular Science Monthly Volume 75.djvu/574

568 able family of born naturalists, the Carrs, told me that he had never seen a bird catch a butterfly, and this has almost or quite been my experience too. In Trinidad, for instance, one may see flycatchers catching slow fliers like beetles, by the hour, any day, but never see them pay the slightest attention to any butterfly whatever. I reiterate this here, merely for what it is worth, and am nowise averse to believing that Heliconius is more than ordinarily unpalatable. If it be true that feeding among red or orange flowers has now or formerly so predominated in the life of the red and yellow spotted species, as to make this dress do them more good than harm, it is equally logical that, as in the case of the digging and burrowing animals that I have referred to, with their corresponding rear armaments, butterflies particularly subject to dangerous absorption while feeding, should have been in the whole period of their existence bred to an excessive degree of inedibility. As to the flight of such butterflies as on the one hand, papilios and morphos, and on the other, the "mimetic" groups proper, the former two families comprise between them, the strongest and swiftest of American butterfly flight, and an unsurpassed brilliancy of costume, bright colors not proving, in their case, to be accompanied either by slow flight, or by equally notable unpalatability. On the other hand, the American so-called mimetic groups proper have a middle-class flight apparently well suited to the by no means open under-brush of the forest, where they go about much in the manner of the genus Hipparchia in the north.

Now to glance for a moment at the significance ascribed by entomologists to the injuries which are found along the borders of butterflies' wings.

Perhaps the most highly artificial and strained hypothesis that has been released from duty by the discovery of the use of patterns is the conception that after a million years' experience birds would not inevitably know what part of a butterfly is edible and instinctively seek it, rather than try to eat the tissue-paper pictures of background painted along its wing-borders. This is entirely contrary to the stern rectitude of nature. One might as well hope to fool a ship about her center of gravity, and induce her to float at an angle that did not defer to it, as induce a million-year-long race of eaters of butterflies' bodies to waste energy over these patterns.

A butterfly has, of course, a fairly tough body, and wings that begin tough next to the body, but become mere tissue-paper at the lateral borders. Now, every slightest contact is perilous to the entirety of these borders, and, at the same time every circumstance of the butterfly's life threatens contact to them. Even the wind may blow things against them, and when the butterfly is pursued by an aerial enemy, his own efforts to escape must often bring them into collision with vegetation. Again, if the pursuer be a bird, his swoops bring him into