242 The Naturalist in Nicaragua 
must suppose that, in that great variety of forms, it some- 
times occurred that two species belonging to distinct orders 
somewhat resembled each other in form or colouration, and - 
that the resemblance was gradually increased, when one 
species had special means of protection, by the other being 
benefited the more nearly it approached it in appearance. 
It is to be remarked that the forms imitated have always 
some kind of defence against insectivorous birds or mammals; 
they are provided with stings or unpleasant odours or 
flavours, or are exceedingly swift in flight; excepting where 
inanimate nature is imitated for concealment. Thus I had 
an opportunity of proving in Brazil that some birds, if not all, 
reject the Heliconii butterflies, which are closely resembled 
by butterflies of other families and by moths. I observed a 
pair of birds that were bringing butterflies and dragon-flies 
to their young, and although the Heliconii swarmed in the 
neighbourhood and are of weak flight so as to be easily caught, 
the birds never brought one to their nest. I had a still better 
means of testing both these and other insects that are 
mimicked in Nicaragua. The tame white-faced monkey I 
have already mentioned was extremely fond of insects, and 
would greedily munch up beetle or butterfly given to him, and 
I used to bring to him any insects that 1 found imitated by 
others to see whether they were distasteful or not. I found 
he would never eat the Heliconii. He was too polite not to 
take them when they were offered to him, and would some- 
times smell them, but invariably rolled them up in his hand 
and dropped them quietly again after a few moments. There 
could be no doubt, however, from the monkey’s actions, that 
they were distasteful to him. A large species of spider 
(Nephila) also used to drop them out of its web when I put 
them into it. Another spider that frequented flowers seemed 
to be fond of them, and I have already mentioned a wasp 
that caught them to store its nest with. 
Amongst the beetles there is a family that is just as much 
mimicked as the Heliconii are amongst the butterflies. These 
are the Lampyride, to which the fireflies belong. Many of 
the genera are not phosphorescent, but all appear to be dis- 
tasteful to insectivorous mammals and birds. I found they 
were invariably rejected by the monkey, and my fowls would 
not touch them. 
