HORTICULTURISTS 227 



Among our wood-boring beetles we have several 

 species of Tomicus. Some allied species in the 

 United States appear at first sight to have the 

 horticultural habit. They live in a common 

 burrow, which is not usual with wood-boring 

 beetles, and on the accumulations of their excrement 

 peculiar fungi grow, which the beetles feed upon. 



Hubbard says that some species do actually 

 cultivate these fungi, and make elaborate prepara- 

 tions of a mushroom-bed to induce their growth. 

 If these beetles have learned the trick from the 

 ants, they have not learned it thoroughly. The 

 ants keep the fungus under control by leaving air- 

 space around their bed, and so restrict the increase 

 of the fungus within limits. In the narrow spaces 

 of beetle-burrows there is not room for this, so it 

 is said that the growth of the fungus is sometimes 

 more rapid than the eaters can keep pace with. 

 In consequence, it plugs up the exit of the burrow 

 so effectually that the beetles are suffocated. We 

 think that in this case, though the beetles may 

 avail themselves of the fungus as food, its presence 

 is merely adventitious and not the result of anything 

 that can be regarded as cultivation. 



