86 Mr. A. Murray on the Relations 



and when it gets to its food (the wasp-grub), it has a tough 

 skin for its tender young jaws to break through before it can 

 begin, and must encounter the risk of being lirst gobbled up 

 by the big wasp-grub, whose jaws are gaping for food at the 

 very door. It seems to me that it would be a safe speculation 

 to lay long odds on the wasp-grub having the best of it. If 

 Mr. Smith says it is not fed at all until it takes a wasp-grub 

 at unawares, then I invite him to consider the difficulties at- 

 tending the promenade which he supposes it to make before 

 breaking its fast. If he admits that it must be fed by the 

 wasps to begin with, then I ask him to say, on abstract grounds 

 (])utting Mr. Stone's observations out of view for the present), 

 why he should object to its being fed by the wasps more at 

 one time of its life than another. 



But there are more anomalies in Mr. Smith's way than that. 

 Suppose that it does not require to be fed, or that, if it requires to 

 be fed, it is fed by the wasps until it reaches its victim, and that 

 then it escapes its jaws and fastens upon it, I want Mr. Smith 

 to say whether it feeds only upon one victim, or if, after eat- 

 ing it up, it comes out again, and goes roaming about from 

 cell to ceil, destroying a succession of grubs. It must do either 

 the one or the other. Let us test both. First, that it only 

 destroys one grub. As the Rhi2nphorus-])\\^K. and perfect in- 

 sects ready to come out are always found in cells closed-in by 

 a lid which Mr. Smith maintains to be spun by the wasp- 

 larva?*, the Rht2)ij>I/07'us-gv\ib must make its lodgment in 

 the victim's cell just before it is beginning to spin, and must 

 make so little progress in its attack upon it at first as to leave 

 it at least power to spin the lid. When it is spun, the two 

 will then be shut up together, and the little tiny grub has full 

 scope to tear away at the vitals of the waspj probably noAV 

 become a pupa. But does Mr. Smith think that a meal of one 

 animal can suffice to nourish another into as great dimensions 

 as the animal eaten. True, a caterpillar infested with ichneu- 

 mons often nourishes within its bosom a tribe of parasites 

 whose aggregate bulk is not much inferior to its own ; but 

 they have not had merely a mass to eat equal to its bulk ; 

 they have grown with its growth, and fresh food has been 

 assimilated for them day by day — so that they have eaten the 



* I have to acknowledge the justness of Mr. Smith's correction of a 

 lapstis penn(B in my last paper, where I spoke of the pupre spinning these 

 lids, instead of the larvae. The contrast in my line of thought was not 

 between pupae and larvfe, but between the lid being spun by the creature 

 inside the cell or lid, or by the parents outside. Of course when the larva 

 changes into a nearly motionless inactive pupa, there could be no ques- 

 tion of spinning. The error corrected itself. 



