30O 



Beetles 



have special habits which make them comparable in some ways with the 

 social wasps, bees, and ants, and with the termites. They live in mines — 

 the "black holes" often seen in tim!)er — bored into the heart-wood of sick 

 or dead trees, in colonies including numerous adults and many larvE. Their 

 food is not the wood of the tree, but consists of certain minute and succulent 

 bodies produced by a fungus which grows on the walls of their burrows. 

 This fungus does not grow there by chance, but is "planted" by the beetles. 

 It is started by the female upon a carefully packed bed or layer of chips, 

 sometimes near the entrance of a burrow, in the bark, but generally at the 

 end of a branch gallery in the wood. It spreads, or is spread, from this 

 forcing-bed to the walls of the various galleries and chambers of the mine. 

 The young larva; nip off the tender tips of the fungus stalks "as calves crop the 

 heads of clover," but the older larvae and adult beetles eat the whole structure 

 down to its base, from which new hy])ha; soon spring up afresh. The fungus 

 is suitable for the insects only when fresh and juicy: if allowed to ripen, the 

 tender protoplasm is shut up in spores, and the galleries are soon filled to 

 suffocation with these spores and the ramifying mycelial threads. Indeed 

 the colony of ambrosia-beetles — ambrosia being the name applied to the 

 tender fungus food — is often overwhelmed and destroyed by the quick 

 growth of their garden-patch. If anything happens to interrupt the constant 

 feeding on and cutting back of the fungus, the colony is ahiiost always 

 destroyed 



