THE WEB OF LIFE 353 



of their food ; they plunder the worker-ants returning to 

 the nest with spoils ; they steal from the newly-fed larvae ; 

 they insist on having a share when the ants are eating ; 

 and, finally, they sometimes demand food from the ants, 

 raising their forelegs in a pecuhar fashion. In this move- 

 ment and in that of the antennse, there seems to be some- 

 thing like an imitation of the ants' movements, but in other 

 ways their movements are conspicuously different. Why 

 the ants tolerate them, who can tell ? It is interesting to 

 note that M. acervorum is purely parthenogenetic, and it is 

 probable that some other species are partially so. The 

 eggs of M. acervorum, and probably of other species, are 

 laid in the nests of the host, and the fact that they are few 

 in number and large in size with much yolk may perhaps 

 be correlated with the safe and luxurious conditions which 

 the mothers have found as semi-parasites in the ants' nest. 

 In some cases of ' myrmecophily ' the hosts get a little in 

 the way of quid pro quo, but what return do these httle 

 crickets make save an occasional kiss ? It is easy to under- 

 stand the crickets being content, but why the ants tolerate 

 their presence is a mystery. If they thought of it, they 

 could soon kill them off, for ants can combine and they can 

 bite or sting, but they do not think of it. Perhaps we make 

 an artificial problem by using words like ' guest ' and ' host ', 

 perhaps the truth is that the crickets do not matter much 

 as long as they are not too numerous. Perhaps and per- 

 haps and perhaps. 



Ivar Tragardh has described the occurrence of the larvae 

 of a Tineid moth in the nests of a New Zealand termite, 

 and the story is very quaint. The larvae depend upon the 

 material of the nest for their food, and they may be seen 

 moving along in file, at regular intervals as if in a procession, 



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