70 NATURAL SELECTION in 



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 Fertebrata 



Having thus shown how varied and extraordinary are the 

 modes in which mimicry occurs among insects, we have now 



