The Sitares 



is struggling as though to set herself at 

 liberty. This explains the presence here, the 

 pairing and the egg-laying of the Sitares 

 whom we but now saw roaming, in the com- 

 pany of the Anthrax-flies, at the entrance to 

 the galleries of the AnthophorcC. The Os- 

 mia and the Anthophora, the joint owners of 

 the premises, have each their parasite: the 

 Anthrax attacks the Osmia and the Sitaris 

 the Anthophora. 



But what is this curious shell in which the 

 Sitaris is invariably enclosed, a shell unex- 

 ampled in the Beetle order? Can this be a 

 case of parasitism in the second degree, that 

 is, can the Sitaris be living inside the chrysalis 

 of a first parasite, which itself exists at the 

 cost of the Anthophora's larva or of its pro- 

 visions? And, even so, how can this para- 

 site, or these parasites, obtain access to a cell 

 which seems to be inviolable, because of the 

 depth at which it lies, and which, moreover, 

 does not reveal, to the most careful examina- 

 tion under the magnifying-glass, any violent 

 inroad on the enemy's part? These are the 

 questions that presented themselves to my 

 mind when for the first time, in 1855, I ob- 

 served the facts which I have just related. 

 Three years of assiduous observation enabled 

 me to add one of its most astonishing chap- 

 37 



