PEOTBCTIVE COLOKATION. 147 



tliere is a tendency to assume their gullibility without bringing 

 forward any proofs. As a matter of probability, it seems 

 likely that most insects would be indifferent to the appearance 

 of an object, provided that it remained motionless ; the frog, 

 of course, does remain motionless. The European tree frog 

 has been stated to have an inordinate appetite for wasps, 

 which surpasses that of other frogs ; there are enough wasps 

 and other brightly coloured Hymenoptera about trees to afford 

 sufficient food for the tree frogs, and it would be opposed to 

 the theory of warning colours to imagine that a gaily coloured 

 wasp, trusting to its formidable weapon, would be especially 

 wary. 



