282 THE COLOURS OF ANIMALS 



ichneumon stings, or perhaps the result of a struggle 

 with some insect enemy, in which the larva has been 

 wounded. The blood of caterpillars forms a black clot, 

 so that wounds are nearly always black until after 

 the next change of skin. 



This is another form of mimetic resemblance the 

 deceptive appearance of the traces left by an enemy 

 suggesting that the larva is already ' occupied.' 



The larva of Stauropus fagi therefore bristles with 

 defensive structures and methods. At rest, it is con- 

 cealed by a combination of the most beautiful Protec- 

 tive Eesemblances to some of the commonest objects 

 which are characteristic of its food-plant. Attacked, 

 it defends itself by a terrifying posture, made up 

 of many distinct and highly elaborate features, all 

 contributing to this one end. Further attacked, it 

 reveals marks which suggest that it can be of no 

 interest to an insect enemy, for another parasite is 

 already in possession. 



The failure of this combination of defensive methods 



The caterpillar is so rare in this country that we 

 know but little of the enemies which attack it. Two 

 parasites are, however, mentioned in Mr. Bignell's list. 

 Its very rarity, however, proves the constant failure of 

 all defensive measures. There is little doubt that the 

 larva is in the same position as that of the Puss Moth, 



