276 THE COLOUES OF ANIMALS 



the ichneumon would probably escape the shower of 

 formic acid. I have never witnessed the attack, but I 

 imagine that the ichneumon swoops down upon the 

 back of the larva just behind the head, and holds on so 

 tightly with its sharp claws that it cannot be dislodged 

 by the violent struggles of the caterpillar. Probably 

 many fail and are struck by the acid showier, w^hich 

 has a very fatal' effect upon them. 



I have enclosed ichneumons of the genus Paniscus 

 in a glass cylinder containing the larvaB. The latter 

 showed not the slightest sign of any knowledge of 

 the presence of their deadly foes, until accidentally 

 touched by the ichneumons as they were hurrying 

 up and down in their endeavours to escape. The 

 instant the larv£e were touched they assumed the 

 terrifying attitude and turned towards the spot, the 

 lips of the opening of the gland swollen by pressure 

 from within, in readiness for an immediate discharge. 

 When an ichneumon was held in the forceps and thus 

 made to touch the caterpillar several times, the fluid 

 was ejected almost instantly, while the larva also 

 made vigorous efforts to bite its enemy with its 

 powerful mandibles. A little of the secretion was 

 collected m a tube and placed on the ichneumons, 

 which collapsed at once, and either died or took many 

 hours to recover. 



When once the eggs are fixed the larva is doomed ; 

 the maggots begin sucking its juices as soon as their 

 heads emerge from the egg-shell, while the tail remains 



