3.2 ON THE ORIGIN AND [CHAP. 



pupae sooner than the females, and M. Fabre ascer- 

 tained that, as they come out of their galleries, the 

 little Sitaris larvae fasten upon them. Not, however, 

 for long: instinct teaches them that they are not yet 

 in the straight path of development ; and, watching 

 their opportunity, they pass from the male to the 

 female bee. Guided by these indications, M. Fabre 

 examined several cells of the Anthophora : in some, 

 the egg of the Anthophora floated by itself on the 

 surface of the honey ; in others, on the egg, as on a 

 raft, sat the still more minute larva of the Sitaris. 

 The mystery was solved. At the moment when the 

 egg is laid the Sitaris larva springs upon it. Even 

 while the poor mother is carefully fastening up her 

 cell, her mortal enemy is beginning to devour her 

 offspring : for the egg of the Anthophora serves not 

 only as a raft, but as a repast. The honey which is 

 enough for either, would be too little for both ; and 

 the Sitaris, therefore, at its first meal, relieves itself 

 from its only rival. After eight days the egg is con- 

 sumed, and on the empty shell the Sitaris undergoes 

 its first transformation, and makes its appearance 

 in a very different form, as shown in Fig. 10. 



The honey which was fatal before is now necessary ; 

 the activity which before was necessary is now use- 

 less ; consequently, with the change of skin, the 

 active, slim larva changes into a white, fleshy grub, 

 so organized as to float on the surface of the honey, 

 with the mouth beneath, and the spiracles above the 

 surface : "grace a 1'emboapoint du ventre," says M. 

 Fabre, " la larve est a 1'abri de 1'asphyxie." In this 

 state it remains until the honey is consumed : then the 



