and Relations of the Wasj) and Ehipiphorus. 355 



we can find reversed pupse is when there are two in the cell. 

 It is only under such circumstances that one can conceive the 

 grub taking the reversed position. In the ordinary case of only 

 one grub in the cell, it is so small when it first comes out 

 of the egg, that it can turn and shift its position as it likes ; 

 and of course the position it likes will be that with its mouth 

 to the food-bringer. But when there are two, if the egg first 

 evolved be lowest, or, what is the same thing, if the grub first 

 out has taken its position at the base of the cell with its head 

 to the mouth of the cell, when the last evolved breaks out of 

 the egg, the latter will naturally turn its head down to that of 

 the former when it receives its food, in order to partake of it, 

 and will gradually settle into that position until it grows too 

 big to have room to change it. I am also inclined to believe 

 that the only case in which two puj)£e are found in one cell is 

 when one of them is a Rkiprphorus. 



I have only, in conclusion, to say that evidence of the accu- 

 racy of all the facts above recorded is, I think, to be seen 

 in the collection in the South-Kensington Museum. As 

 already said, I have not sufficient acquaintance with the eco- 

 nomy of wasps and bees to be sure that the occurrence of 

 reversed pupte and grubs, although new to me, is not per- 

 fectly well known to hymenopterists, and that all the points 

 I have been boggling at have not been clearly and satisfactorily 

 explained ; but I know that if they have not been previously 

 observed, they will have and ought to undergo the usual 

 scrutiny of doubt and suspicion. To any one who shall feel 

 so far interested in the subject as to wish to test them, I 

 would recommend the little black saucer of droppings taken 

 from the mouths of the cells of the reversed pupse as a good 

 "piece justijicatif.^'' Its shape will tell that it did not come 

 from the base of the cell, but must have come from the mouth. 

 One of these is left actually in situ under the lid of the cell or 

 cocoon ; another is in a phial of Canada balsam (as to which, 

 however, I may add the scarcely necessary caution that its 

 position in relation to the pupa in the phial is not the natural 

 one : when I put it in, its tail was still attached to it ; but 

 it became detached; and, in settling, it has wheeled round and 

 its mouth come into contact with the black saucer ; but no one 

 knowing the nature of the saucer will mistake that for its 

 natural position). The pupge from these doubly tenanted cells 

 are also there ; and if there is anything I have overlooked, it 

 is, I hope, unnecessary to say that I shall be happy to supply 

 it to those who may wish to know more, if they will specify 

 the points on which they desire information. . 



