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SO many species to co-exist within very narrow limits, 

 so that even three or four distinct kinds sometimes 

 form their nests so close to each other that their 

 galleries interlace and almost touch. 



There are probably very few conditions of life 

 (except those concerned with the nature and manner 

 of obtaining food) which have a greater influence 

 either in keeping creatures apart or in bringing them 

 into collision, than those which constitute differences 

 in their respective periods of activity and development. 

 Thus, two species of which one has nocturnal and the 

 other diurnal habits, or of vv^hich one is dormant while 

 the other is active, may be said to travel different 

 roads and to be complete strangers to one another. 

 Complete separation of this kind is, of course, not the 

 rule, and the greater number of species find them- 

 selves in more or less constant rivalry, but possess a 

 sufficient number of points of dissimilarity in habit 

 and requirements to make their co-existence possible. 



It is curious to note what little differences, as they 

 seem to us, may determine the fate of an ant. For 

 example, the lizards will lie in wait for and greedily 

 seize and devour the winged males and females of 

 dructor and harbara, though they dare not attack the 

 assembled workers. It is curious to watch the way 

 in which these worker ants will protect the winged 

 ants which are about to leave the nest, by gathering 

 round and swarming over them. When, as often 

 happens, the nest is placed in an old terrace-wall, one 

 may see the lizards creeping along or lying moulded 

 into the inequalities of the stones, all having their 

 eager eyes directed towards the swarm. One may 

 then see the worker ants walk with impunity straight 



