64 THE SOLITARY WASPS. 



two great goggle eyes, had an irresistibly comical aspect. With 

 the exception of the omnipresent flies, this wasp was the only 

 sign of life about the place. Even in good weather and in 

 working hours, the wasps sometimes rest, for we have seen 

 them go in empty handed, closing the door behind them, to 

 remain for half an hour at a time. 



There is one thought that must strike the most casual ob- 

 server of a colony like this. Why do not these wasps, fly- 

 catchers as they are by profession, kill the parasitic flies that 

 infest their homes, thriving abundantly on the fruits of their 

 labor, a continual menace to the life and safety of their off- 

 spring ? To the uninitiated it would seem that these flies would 

 serve as food for the wasp larvas quite as well as any of the 

 dozen species that they actually take, but even if the wasp-mother 

 believes that they possess indigestible qualities, it would be 

 much less trouble to kill them and throw them away than to be 

 perpetually chasing them to a little distance only to see them 

 return as soon as she gives her attention to anything else. 

 Whatever the reason for it may be the relation between the 

 wasps and the flies is certainly most curious and puzzling. 

 Fabre's explanation is that since this miserable little fly has its 

 own part to play in nature, Bcmhex must respect it, thus pre- 

 serving harmony in the world of living things. The idea is 

 perfectly in accord with his own theories, but we find ourselves 

 quite unable to accept it. 



There can be no doubt that the parasites are a grave danger 

 to Bemhex. She suffers from them far more than any other 

 wasp that we are familiar with, her mode of feeding the young 

 rendering her peculiarly susceptible to their attacks. Of the 

 ten or twelve nests that we opened only one was free from 

 them, the others containing from two to five lively maggots 

 nearly as large as the wasp larvae, which were sharing the food 

 brought in by the mother. Fabre, who has studied the ques- 

 tion thoroughly, has found as many as ten parasitic larvae in one 

 nest. He has also noticed that where the parasites are most 

 numerous the wasp-larva is proportionately small and cmaciat- 



