xlix 



to be most unpalatable, she never makes any attack on her 

 enemy. Nay, when the young of the Miltogramma are hatched, 

 so far from killing or removing them, this entomological cuckoo 

 actually feeds them until they reach maturity. Nevertheless it 

 seems contrary to etiquette for the fly to enter the cell of the 

 Bemhex ; she watches the opportunity when the latter is in the 

 cell and is dragging down the victim. Then is the Miltogramma' s 

 opportunity; she pounces on the victim, and almost instan- 

 taneously lays on it two or three eggs, which are then transferred, 

 with the insect on which they are to feed, to the cell. 



It is remarkable how the Bemhex remembers (if one may use 

 such a word) the entrance to her cell, covered as it is with sand, 

 exactly to our eyes like that all round. Yet she never makes a 

 mistake or loses her way. On the other hand, M. Fabre found 

 that if he removed the surface of the earth and the passage, 

 exposing the cell and the larva, the Bemhex was quite at a loss, 

 and did not even recognise her own offspring. It seems as if she 

 knew the door, the nursery, and the passage, but not her child. 



Another ingenious experiment of M. Fabre's was made with 

 Chalicodoma. This genus is enclosed in an earthen cell, through 

 which at maturity the young insect eats its way. M. Fabre found 

 that if he pasted a piece of paper round the cell the insect had 

 no difficulty in eating through it ; but if he enclosed the cell in a 

 paper case, so that there was a space even of only a few lines 

 between the cell and the paper, in that case the paper formed an 

 effectual prison. The instinct of the insect taught it to bite 

 through one enclosure, but it had not wit enough to do so a 

 second time. 



Yet it appears that the instincts of these animals are not 

 absolutely unalterable. Sphex flavipennis, which provisions its 

 nest with small grasshoppers, when it returns to the cell leaves 

 the grasshopper outside, and goes down for a moment to see 

 that all is right. During her absence M. Fabre moved the 

 grasshopper a little. Out came the SjjJiex, soon found her 

 victim, dragged it to the mouth of the cell, and though she had 

 just been down left her prey as usual, and went alone into the 

 cell. Again M. Fabre moved the grasshopper, the wasp found 

 it, dragged it to the cell, and left it as before. Again and again 

 M. Fabre moved the grasshopper, but every time the Sjjhex did 

 exactly the same thing, until M. Fabre was tired out. All the 



