228 SOCIAL LIFE IN THE INSECT WORLD 



burrows are numerous. Let us dig, then, in the 

 neighbourhood of these holes. The sign is reUable ; 

 in a few hours, thanks to the signs of the Bolboceras, 

 I obtain a handful of specimens of the Hydnocystis. 

 It is the first time I have ever found this fungus in 

 the ground. Let us now capture the inSect — an easy 

 matter, for we have only to excavate the burrows. 



The same evening I begin my experiments. A wide 

 earthen pan is filled with fresh sand which has been 

 passed through a sieve. With the aid of a stick the 

 thickness of a finger I make six vertical holes in the 

 sand : they are conveniently far apart, and are eight 

 inches m depth. A Hydnocystis is placed at the bottom 

 of each ; a fine straw is then inserted, to show me the 

 precise position later. Finally the six holes are filled 

 with sand which is beaten down so thr.t all is firm. 

 When the surface is perfectly level, and everywhere the 

 same, except for the six straws, which mean nothing to 

 the insect, I release my beetles, covering them with a 

 wire-gauze cover. They are eight in number. 



At first I see nothing but the inevitable fatigue due 

 to the incidents of exhumation, transport, and confine- 

 ment in a strange place. My exiles try to escape : they 

 climb the wire walls, and finally all take to earth at the 

 edge of their enclosure. Night comes, and all is quiet. 

 Two hours later I pay my prisoners a last visit. Three 

 are still buried under a thin layer of sand. The other 

 five have sunk each a vertical well at the very foot 

 of the straws which indicate the position of the buried 

 fungi. Next morning the sixth straw has its burrow 

 like the rest. ^ 



It is time to see what is happening underground. 



