THE FUNGUS-GROWING ANTS. 



325 



form truncated cones of dead leaves and twigs, beneath which they 

 excavate a single chamber containing a large fungus garden sometimes 

 1.5 meters long. A. iiurllcri has similar habits, but coronata resembles 

 the species of the subgenus Atta s. sir. in forming several chambers, 

 each with its own fungus garden. In all of these species the garden is 

 built up on the floor of the chamber in the form of a loose sponge-work 

 of triturated leaf-fragments, permeated with fungus hyplue which he 



FIG. 193. Tower-shaped nest crater of Trachymyrmex titrrife.r in Texan cedar 

 brake; natural size. (Photograph by A. L. Melander.) 



describes as follows: "Over all portions of the surface of the garden 

 are seen round, white corpuscles about .25 mm. in diameter on an 

 average, although some of them are fully .5 mm., and sometimes adja- 

 cent corpuscles fuse to form masses i mm. across and of irregular 

 form. After a little experience one learns to detect these corpuscles 

 with the naked eye as pale, white points which are everywhere abundant 

 in all nests. Under the lens they sometimes have a glistening appear- 

 ance like drops of water. They are absent from the youngest, most 

 recently established portions of the garden, but elsewhere uniformly 

 distributed, so that it is impossible to remove with the fingers a particle 

 too small to contain some of the white bodies. I call these the ' kohl- 

 rabi clusters' of the ants' nests. They constitute the principal, if not 



