14 INSECTS ABROAD. 



" The answer is, that the dark-coloured kind has means of 

 protection of quite a different nature, and therefore does not 

 need the peculiar mode of disguise enjoyed by its companion. 

 When handled it emits a strong, offensive, putrid, and musky 

 odour, a property which the pale kind does not exhibit. Thus 

 we see that the fact of some species not exhibiting the sanio 

 adaptation of colours to dwelling-places as their companion 

 S]:)ecies, does not throw doubt on the explanation given of the 

 adaptation, but is rather confirmatory of it:' 



The problem which Mr. Bates endeavours thus partially to 

 solve is a very curious and interesting one, and certainly is not 

 settled by Mr. Bates's explanation. Were it true that all these 

 insects were protected in one way or another, none of them would 

 ever be eaten by other creatures. It is perfectly true that many 

 insects are coloured so as to resemble the spots wherein they 

 hide, and therefore escape the observation of birds and other 

 insect-eaters. Some, again, resemble in shape as well as in 

 colour the vegetation on which they live, such as tlie well- 

 known caterpillars of the Geometry, or Loopers, which so exactly 

 resemble twigs that none but an entomologist could detect 

 them. So far so good, but, I think, no further. I am inclined 

 to demur to Mr. Bates's theory of the protection afforded by the 

 evil odour of which he writes, and for this reason. Odours are 

 grateful or the reverse according to the constitution of the 

 smeller. For example, even in our own sense the apprecia- 

 tion of odours varies extremely. The close, filthy, foetid atmo- 

 sphere of an Irish cabin, which almost chokes an average 

 Englishman, is like the breath of Paradise to the peasant 

 owner. Put him in a large, clean, bright room, and he will 

 complain of the cold, and make for himself a cabin in one 

 corner, where he can be dirty and warm. Then, our nostrils 

 are generally offended at the smell of rancid grease and un- 

 washed humanity, which to a Kaffir are delightful as the 

 perfume of the rose. To us, the stench of a putrefying animal 

 is inexpressibly odious, and even hurtful, while to the vultures, 

 and to whole tribes of insects, it is the delight of their lives. 

 Therefore, though the odour of these highly-coloured, sand- 

 loving Tiger Beetles be very detestable to human nostrils, it 

 does not follow that it should be equally unpleasant to insect- 

 eating birds. 



