220 



THE BIOLOGY OF INSECTS 



galleries, and the grubs when hatched *' wander about in 

 the passages (Fig. 58, P) and feed in company upon the 

 ambrosia which grows here and there upon the walls." 

 Probably each kind of ambrosia beetle " grows its own 

 peculiar fungus in a pure culture," and each female starts a 

 new culture for her offspring by carrying away from the 

 cradle or passage in which she was herself reared a mass of 



Fig. 58, — Galleries of Ambrosia Beetles. Platypus (P) and Gnatho- 

 trichus (G) in pine trunk. North America. The small circles along 

 the course of the galleries, as seen in cross section of trunk, indicate 

 position of the " cradles," which are shown in side-view at G' (e, egg; 

 /, larvae in various stages ; p, pupa ; a, adults waiting for emergence). 

 About natural size. After J. M. Swaine. (Canad. Dept. Agric. Ent. 

 Bull. 7, 1914.) 



spores, either on her head, in her jaws, or in the front 

 region of her stomach, whence they are regurgitated when 

 she has reached a site suitable for the foundation of a 

 new family. 



Most remarkable perhaps of all the social beetles are 

 two forms of the family Cucujidae recently found by Wheeler 

 living in the hollow leaf-stalks of young Tachigalia trees of 



