52 THE WONDER OF LIFE 



form of mites, unfriendly intruders, indifferent fellow- 

 tenants, occasional ' cows ' (as Linnaeus called the 

 Aphides), and pets. These pets are usually Staphylinid 

 beetles belonging to the family well-represented in 

 Britain by the devil's coach-horse (Ocypus olens). Some 

 of the Staphylinids are downright robbers and others are 

 merely tolerated by the ants, but there is a third set 

 (represented by the genera Atemeles and Lomechusa) to 

 which the name of pet may be applied. These beetles 

 are never found outside or at any rate very far from the 

 ants' nests ; they have patches of yellow hairs which 

 seem to secrete some substance which the ants like to lick ; 

 they seem to be on very friendly relations with the ants, for 

 they stroke them and get drops of honey from their mouths, 

 and they will in turn disgorge some of their repast for the 

 benefit of a hungry host. On the other hand, these friends 

 of the family are not so innocent as they appear, for while 

 with bended knee they will solicit a bonne bouche from 

 their hosts, and while they like to sit among a crowd of 

 ants as if exchanging the compliments of the season, they 

 are on the sly eating up a good many of the ants' children 

 and that when their own are receiving food from the ants. 

 And now we come to our precise point. Looking down 

 through Father Wasmann's eyes on this quaint association 

 of hosts and guests, we feel safe in saying that the presence 

 of the beetles adds to the ants' sum-total of happiness, and 

 yet we cannot avoid doubting whether the amiable hospital- 

 ity of the ' little people, exceeding wise ' has not in it elements 

 of danger. What if the guests became too numerous ? 



As a fine example of wheels within wheels, let us face 

 this question and inquire what actually happens. The 

 beetles are not unlike ants in their ways, and the larvaB of 



