The Sitares 



the Spiders. Among these corpses some 

 male Sitares circle, busy, amorous, heedless 

 of death, mating with the first female that 

 passes within reach, while the fertilized 

 females thrust their bulky abdomens into the 

 opening of a gallery and disappear into it 

 backwards. It is impossible to mistake the 

 situation: some grave interest attracts to this 

 spot these two insects, which, within a few 

 days, make their appearance, mate, lay their 

 eggs and die at the very doors of the 

 Anthophora's dwellings. 



Let us now give a few blows of the pick 

 to the surface beneath which the singular in- 

 cidents already in our mind must be oc- 

 curring, beneath which similar things oc- 

 curred last year; perhaps we shall find some 

 evidence of the parasitism which we sus- 

 pected. If we search the dwellings of the 

 Anthophorae during the early days of August, 

 this is what we see : the cells forming the sup- 

 erficial layer are not like those situated at a 

 greater depth. This difference arises from 

 the fact that the same establishment is ex- 

 ploited simultaneously by the Anthophora 

 and by an Osmia (O. tricornis) ^ as is proved 

 by an observation made at the working- 



1 Cf. Bramble-bees and Others: passim. — Translator's 

 Note. 



31 



