INSECT LIFE 183 



Who are the enemies against which Nature is always 

 protecting these moths and butterflies in their winged 

 state 1 with the shield of colour invisibility? When 

 we look closely we may see the armour, but not the 

 enemy. The pepper and salt moth in the north of 

 England has darkened and darkened within the 

 memory of man, till now the dark form prevails ; 

 whereas in the south it has still as much salt as 

 pepper on the wings. The idea is that this moth 

 has blackened, in a country of black tree trunks and 

 palings, to match its environment, and cheat its foes. 

 But there are like cases of melanism in the Shetland 

 Islands and in the extreme south of England. Besides, 

 who are the deadly enemies of the moths in their 

 winged state ? Mr. Porritt cannot discover them, and 

 I have been in the same difficulty for years. The 

 protection idea is beautiful. I wish I could accept it 

 wholly. It is order. Doubt it, and we seem to invite 

 back disorder. But unless we doubt in these things, I 

 think we cannot reach the truth. 



I must be assured, first, that a creature which puts 

 on the ingenious armour of colour mimicry needs it ; 

 second, that the armour tends to save that creature 

 from its foes. Mere matching of bird, beast, or insect 

 to its environment leaves me a doubter. Even when 

 the creature appears to alter to suit altered environ- 

 ment, as with this pepper and salt moth, I doubt. 



1 Caterpillars, I think, must often have protection through colour 

 and form ; but here I am speaking only of the winged insect. 



