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in PROTECTIVE RESEMBLANCES AMONG ANIMALS 57which catch insects on the wing, and that they destroy manybutterflies is indicated by the fact that the wings of theseinsects are often found on the ground where their bodieshave been devoured. But among these there are no wings ofHeliconidae, while those of the large showy Nymphalidse,which have a much swifter flight, are often met with. Again,a gentleman who had recently returned from Brazil stated ata meeting of the Entomological Society that he once observeda pair of puffbirds catching butterflies, which they brought totheir nest to feed their young ; yet during half an hour theynever brought one of the Heliconidse, which were flying lazilyabout in great numbers, and which they could have capturedmore easily than anyothers. It was this circumstance thatled Mr. Belt to observe them so long, as he could not understandwhy the most common insects should be altogetherpassed by. Mr. Bates also tells us that he never saw themmolested by lizards or predacious flies, which often pounce onother butterflies.If, therefore, we accept it as highly probable (if not proved)that the Heliconidse are very greatly protected from attack bytheir peculiar odour and taste, we find it much more easy tounderstand their chief characteristics their great abundance,their slow flight, their gaudy colours, and the entire absenceof protective tints on their under surfaces. This propertyplaces them somewhat in the position of those curious winglessbirds of oceanic islands, the dodo, the apteryx, and the moas,which are with great reason supposed to have lost the powerof flight on account of the absence of carnivorous quadrupeds.Our butterflies have been protected in a different way, butquite as effectually; and the result has been that as there hasbeen nothing to escape from, there has been no weeding outof slow flyers,and as there has been nothing to hide from,there has been no extermination of the bright-coloured varieties,and no preservation of such as tended to assimilate with surroundingobjects.Now let us consider how this kind ofprotection must act.Tropical insectivorous birds very frequently sit on deadbranches of a lofty tree, or on those which overhang forestpaths, gazing intently around, and darting off at intervals toseize an insect at a considerable distance, which they generally