Imitative Resemblances 241 
some the maxillary palpi are lengthened and thickened so as 
to resemble the head of one. 
Ant-like spiders have been noticed throughout tropical 
America and also in Africa.1 The use that the deceptive 
resemblance is to them has been explained to be the facility 
it affords them for approaching ants on which they prey. I 
am convinced that this explanation is incorrect so far as the 
Central American species are concerned. Ants, and especially 
the stinging species, are, so far as my experience goes, not 
preyed upon by any other insects. No disguise need be 
adopted to approach them, as they are so bold that they are 
more likely to attack a spider than a spider them. Neither 
have they wings to escape by flying, and generally go in 
large bodies easily found and approached. ‘The real use is, 
I doubt not, the protection the disguise affords against small 
insectivorous birds. I have found the crops of some hum- 
ming-birds full of small soft-bodied spiders, and many other 
birds feed on them. Stinging ants, like bees and wasps, are 
closely resembled by a host of other insects; indeed, when- 
ever I found any insect provided with special means of 
defence I looked for imitative forms, and was never disap- 
pointed in finding them. 
Stinging ants are not only closely copied in form and move- 
ments by spiders but by species of Hemiptera and Coleoptera, 
and the resemblance is often wonderfully close.2_ All over the 
world wasps are imitated in form and movements by other 
insects, and in the tropics these mimetic forms are endless. 
In many cases the insect imitating is so widely removed, in 
the normal form of the order to which it belongs, from that of 
the insect imitated, that it is difficult to imagine how the 
first steps in the process of imitation took place. Looking 
however at the immense variety of insect life in the tropics, 
and remembering that in early tertiary times nearly the 
whole world was in the same favourable condition as regards 
temperature (vegetation, according to Heer, extending to 
the poles), and must have supported a vast number of species 
and genera that were destroyed during the glacial period, we 
i See Nature, vol. iii. p. 508. 
* Amongst the longicorn beetles of Chontales- Mallocera spinicollis, 
Neociytus Esopus, and Diphyrama singuiaris, Bates, all closely resemble 
stinging ants when moving about on fallen logs, 
