186 STUDIES, SCIENTIFIC AND SOCIAL chap. 



them ; and nothing would convince them that there was a 

 real live insect there but the test of touch — it had to be 

 stirred up to make it move, or taken off the plant to crawl 

 on the finger of the attendant." 



But these remarkable insects do not stand alone. There 

 are many others in every order which are " disguised " in 

 a somewhat similar manner, some with equal perfection, 

 others less accurately, but all serving the same purpose — 

 that of protecting the insect from the enemies that would 

 destroy it. I propose now to give a short account of some 

 of the more interesting cases that occur both at home and 

 in the more luxuriant regions of the tropics. 



Almost everyone must have noticed the very different 

 way in which the bright colours are distributed in butter- 

 flies and moths. In the former, the whole upper surface 

 of the wings is adorned with equally gay colours, while the 

 under surface is always less brilliant, and is generally 

 blotched or mottled with obscure or simple hues. In most 

 moths, on the contrary, the bright colour is restricted to 

 the upper surface of the lower wings, the upper wings 

 being usually of variously mottled brown or ashy tints. 

 This difference is at once seen to be connected with the 

 habits of the insects, the conspicuous colours being so 

 arranged as to be visible during flight, but hidden in 

 repose. On the other hand, the beautiful mottlings and 

 spots and delicate shadings that cause so many moths to 

 resemble bark or lichens, or leaves or twigs, are never 

 developed on those parts of the wings which are hidden 

 during repose. Thus all the Bombycidse and Noctuidse, 

 which conceal their hind wings when at rest, have them 

 either quite plain or ornamented with rich orange or 

 crimson hues ; while almost all the Geometridoe, which rest 

 with their wings spread open, and such of the Bombycidse 

 as have the same habit, are mottled and tinted alike on 

 both front and hind wings. 



These general facts as to the distribution of colour con- 

 stitute the first stage in that process of " disguise " which 

 becomes so wonderfully developed in a few conspicuous 

 cases. The next stage is exhibited by the fact that there 

 is a general agreement between the colour of a large 



