JUNE 131 



has followed another in giving a wholly erroneous 

 explanation of its methods of waging war. There lies 

 before me — nay, to avoid misunderstanding I will 

 express my meaning differently — I have before me, as 

 I write, one of the latest books on butterflies, published 

 in 1903, in which we are told that the little fly 

 Apanteles lays her eggs in the body of the white 

 butterfly's caterpillar, that the grubs when hatched 

 feed on its interior ' by a wonderful instinct avoiding 

 vital parts,' and eventually bite their way out and form 

 cocoons on the skin of their victim. 



Now, it has been told of a pupil undergoing examina- 

 tion that when asked to say what he knew about a 

 lobster, his answer was, 'A lobster is a red fish that 

 swims backwards.' — ' There are only three mistakes in 

 your answer,' observed the examiner, ' a lobster is not 

 red, it is not a fish, and it does not swim backwards.' 

 Even so in this fable about the ichneumon Apanteles. 

 It does not lay eggs in the caterpillar's body, but in 

 the eggs of the butterfly ; the grubs do not devour the 

 caterpillar's interior, but simply reside there sucking 

 the juices of their host's food; lastly, they do not bite 

 their way out, for they have neither jaws nor teeth, 

 only an orifice for suction. By the time the caterpillar 

 begins to spin in preparation for the pupa stage the 

 little ichneumon grubs are also ready for pupation. 

 They (for there is a whole company of them within 

 the body of the doomed caterpillar) manage to suck 

 a single hole in the weak skin between two segments 

 of their involuntary host's body; the whole troop 

 make their exit thereby and proceed to form each 



