The Sitares 



are devoid of the glandular apparatus de- 

 signed for secreting silk. They therefore 

 never spin a cocoon, but lie naked in their 

 cells, whose inner surface has the polish of 

 stucco. 



In the Osmia's cells, on the other hand, 

 means of defence are required, for these are 

 situated in the surface layer of the bank; 

 they are irregular in form, rough inside and 

 barely protected, by their thin earthen par- 

 titions, against external enemies. The Os- 

 mia's larvae, In fact, contrive to enclose them- 

 selves in an egg-shaped cocoon, dark brown 

 in colour and very strong, which preserves 

 them both from the rough contact of their 

 shapeless cells and from the mandibles of 

 voracious parasites, Acari,^ Cleri ^ and An- 

 threni,^ those manifold enemies whom we 

 find prowling in the galleries, seeking whom 

 they may devour. It is by means of this 

 equipoise between the mother's talents and 

 the larva's that the Osmia and the Antho- 

 phora. In their early youth, escape some part 



1 Mites and Ticks. — Translator's Note. 



~A genus of Beetles of which certain species (Clerus 

 ap'tar'ius and C. alvearius) pass their preparatory state in 

 the nests of Bees, where they feed on the grubs. — Trans- 

 lator's Note. 



3 Another genus of Beetles. The grub of A. musa- 

 orum, the Museum Beetle, is very destructive to insect- 

 collections. — Translator's Note. 

 33 



