Insect Camouflage. 143 



Miiller explains that enemies in learning the distasteful qaalities of 

 these insects would necessarily destroy more of the abundant species 

 than of the rarer one, the loss being divided amongst them in proportion 

 to their numbers ; thus the advantage of the resemblance would be 

 greater to the rarer species. 



Midler's observations were carried out on butterflies belonging to 

 the families Ithomiinae and Heliconiidee. The Ithomiinje although them- 

 selves distasteful mimic the Heliconiidse. 



Loss of Colour. — In all the above examples the camouflage of the 

 insect depends upon the development of a colour pattern ; there are some 

 insects, however, which owe their protection to the loss of colour. 



A notable example is offered by some butterflies of the family 

 Salyridcv. Instead of the wings of these insects beiDg heavily scaled and 

 brightly coloured as in other Lepidoptera they are almost devoid of such, 

 and are quite transparent. Thus any object against which they rest can 

 easily be seen through their wings and they merge into the surroundings. 

 The example given in the figure (tig. 3) ia Hcetera piera L. 



The larvae of some mosquitoes, and their near relatives the 

 Corethrids, also possess this character. When it is remembered that 

 their natural element is water, the advantage of such transparency can 

 be seen. 



Form. — At times form, invariably associated with colour, plays a 

 very important part in camouflage. This is obvious in cases of special 

 protective resemblance and mimicry ; in both of these it is necessary that 

 the shape of the object, as well as its colour, be copied for the protection 

 to succeed. In some insects, however, it is used in a different way. 



There is a family of butterflies, the Lycaeniidae, which have 

 peculiar tail-like structures developed on their hind wings. 

 These " tails " are not the usual swallow-tail arrangements of other 

 butterflies, but slender and complicated structures. Viewed from 

 the side they would seem to have no purpose — except perhaps direc- 

 tive coloration — but when these insects are seen from above it is 

 noticeable how little difference there is between the front and 

 hind ends ; in fact it is the hind end that is most conspicuous. It is 

 supposed that such resemblance serves these insects to the greatest 

 extent, for their enemies are deceived by it, and by attacking the tail the 

 insects escape with their lives. 



Among our butterflies there are many Lycaeniidae or " Blues," but it 

 cannot be said that the majority of them exhibit this character well. 

 There is one, however, in which it is fairly well shown, and this is Thecla 

 linus sulz. It can well be understood that this camouflage must often be 

 effective. 



