TU PROTECTIVE RESEMBLANCES AMONG ANIMALS 57 
which catch insects on the wing, and that they destroy many 
butterflies is indicated by the fact that the wings of these 
insects are often found on the ground where their bodies 
have been devoured. But among these there are no wings of 
Heliconidz, while those of the large showy Nymphalide, 
which have a much swifter flight, are often met with. Again, 
a gentleman who had recently returned from Brazil stated at 
a meeting of the Entomological Society that he once observed 
a pair of puffbirds catching butterflies, which they brought to 
their nest to feed their young; yet during half an hour they 
never brought one of the Heliconide, which were flying lazily 
about in great numbers, and which they could have captured 
more easily than any others. It was this circumstance that 
led Mr. Belt to observe them so long, as he could not under- 
stand why the most common insects should be altogether 
passed by. Mr. Bates also tells us that he never saw them 
molested by lizards or predacious flies, which often pounce on 
other butterflies. 
If, therefore, we accept it as highly probable (if not proved) 
that the Heliconide are very greatly protected from attack by 
their peculiar odour and taste, we find it much more easy to 
understand their chief characteristics—their great abundance, 
their slow flight, their gaudy colours, and the entire absence 
of protective tints on their under surfaces. This property 
places them somewhat in the position of those curious wingless 
birds of oceanic islands, the dodo, the apteryx, and the moas, 
which are with great reason supposed to have lost the power 
of flight on account of the absence of carnivorous quadrupeds. 
Our butterflies have been protected in a different way, but 
quite as effectually; and the result has been that as there has 
been nothing to escape from, there has been no weeding out 
of 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 sur- 
rounding objects. 
Now let us consider how this kind of protection must act. 
Tropical insectivorous birds very frequently sit on dead 
branches of a lofty tree, or on those which overhang forest 
paths, gazing intently around, and darting off at intervals to 
seize an insect at a considerable distance, which they generally 
