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NATURAL SELECTION 
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as the British genus Volucella and many of the tropical 
Bombylii, and most of these are exactly like the particular 
species of bee they prey upon, so that they can enter their 
nests unsuspected to deposit their eggs. There are also bees 
that mimic bees. The cuckoo bees of the genus "Nomada are 
parasitic on the Andrenidse, and they resemble either wasps 
or species of Andrena ; and the parasitic humble bees of the 
genus Apathus almost exactly resemble the species of humble 
bees in whose nests they are reared. Mr. Bates informs us 
that he found numbers of these “ cuckoo ” bees and flies on 
the Amazon, which all wore the livery of working bees 
peculiar to the same country. 
There is a genus of small spiders in the tropics which feed 
on ants, and they are exactly like ants themselves, which no 
doubt gives them more opportunity of seizing their prey ; and 
Mr. Bates found on the Amazon a species of Mantis which 
exactly resembled the white ants which it fed upon, as well 
as several species of crickets (Scaphura), which resembled in 
a wonderful manner different sand-wasps of large size, which 
are constantly on the search for crickets with which to 
provision their nests. 
Perhaps the most wonderful case of all is the large cater- 
pillar mentioned by Mr. Bates, which startled him by its 
close resemblance to a small snake. The first three segments 
behind the head were dilatable at the will of the insect, and 
had on each side a large black pupillated spot, which re- 
sembled the eye of the reptile. Moreover, it resembled a 
poisonous viper, not a harmless species of snake, as was 
proved by the imitation of keeled scales on the crown produced 
by the recumbent feet, as the caterpillar threw itself backward ! 
The attitudes of many of the tropical spiders are most 
extraordinary and deceptive, but little attention has been 
paid to them. They often mimic other insects, and some, 
Mr. Bates assures us, are exactly like flower buds, and take 
their station in the axils of leaves, where they remain motion- 
less waiting for their prey. 
Cases of Mimicry among the Vertebrata 
Having thus shown how varied and extraordinary are the 
modes in which mimicry occurs among insects, we have now 
