354 Mr. A. Murray on the History 



any one who looks at an unexcluded pupa nearly mature, when 

 he will see it is clothed in a hardened cake of it all over. 



This may explain the spinning of the lids to the cells of 

 reversed wasp-pupae ; but what shall we say to those of the 

 Rhipiphori ? Have they the same Jluida sericina ? I suppose 

 they must ; but we want observation on this point; and for the 

 present I must content myself with having pointed out the 

 want. 



These reversed larvae present other difficulties. How do 

 they maintain their place in this unnatural position ? Nor- 

 mally their position is head downmost (not in reference to the 

 cell, but to the ground). The cell has its mouth downwards, 

 and the head of the grub is at the mouth of the cell. In that 

 position one would expect it to fall out ; but it uses its tail as 

 a sucker, and hangs on by it. When you pull them out of 

 the cell, you have to give a tug to bring them away. Reverse 

 it, and it might hang on like a sailor by the teeth for a little, 

 but certainly could not do so for any length of time. It must 

 in any event sometimes open its jaws to eat, and it would then 

 fall out. I suppose it must hold on as usual by the tail ; only, 

 instead of fastening itself at the base of the cell, it will do so 

 on the sides of the mouth of the cell. It would have the dis- 

 advantage of the weight of the body pressing on the tail, in- 

 stead of hanging from it ; but I can see no other way in which 

 it could be done. In the pupa-state both the reversed speci- 

 mens had the tail adhering as a sucker to the black saucer of 

 debris lying in the lid of the cell. 



The manner in which these reversed larvae can have been 

 fed is another puzzle. Miss Eleanor Ormerod suggests that 

 it may have been through an opening towards the base in an 

 adjoining cell ; but I can find no such opening, and, moreover, 

 all the surrounding cells were themselves tenanted. It some- 

 how seems not quite so difficult to imagine how it could be 

 done with two larvee in the cell (the one at the mouth reversed 

 and the other not) as it would be with only one, reversed. 

 The grub in the latter would have its mouth so far in the cell 

 that the wasp coming with food might not be able to reach it; 

 but when there are two (arranged as supposed), the inner one, 

 of course, both has its own head halfway to the opening, 

 and directed towards it, and also prevents the other going so 

 far into the cell, and its head must just meet that of the inner 

 one. Thus, if the wasp gets at the mouth of the inner one to 

 feed it, the upper reversed one must always have the oppor- 

 tunity of taking a share of what is given to it. 



I feel rather inclined to suppose that the only case in which 



