The Hunting Wasps 



only food of her family of grubs. I do not 

 speak of the unsurmountable difficulties 

 which this breeding would present. We 

 have not to do with the Bee, who is faithful 

 to her hive, because of her social habits; still 

 less with the stupid Silkworm, perched on its 

 mulberry-leaf, or its clumsy Moth, who for 

 a moment flutters her wings, pairs, lays her 

 eggs and dies: we have to do with an insect 

 that is capricious in its wanderings, swift of 

 flight and independent in its ways. 



Besides, the first condition shatters all our 

 hopes. Would we have the helpful Ammo- 

 phila? Then we must resign ourselves to 

 accepting the Grey Worm. We move in a 

 vicious circle: to produce good we must in- 

 voke the aid of evil. The hostile band 

 brings the friendly troop to our fields; but 

 the second cannot live without the first; and 

 the two show an even balance in numbers. 

 If the Grey Worm abound, the Ammophila 

 finds copious provender for her grubs and 

 her race prospers; if the Grey Worm be rare, 

 the Ammophila's offspring decrease and dis- 

 appear. This balance between prosperity 

 and decadence is the immutable law that gov- 

 erns the proportions between devourers and 

 devoured. 



384 



