244 INSECT LIFE xvm 



still upon the sand, near the nest. It is a small 

 Dipteron — nothing at all to look at — of inoffensive 

 aspect. This petty fly is the terror of the Bembex. 

 That bold assassin of Diptera, who so promptly twists 

 the neck of colossal gadflies, full fed on blood from 

 an ox's back, dares not enter her home because she 

 sees herself watched by another Dipteron — a mere 

 pigmy, which would scarce make one mouthful for 

 her larva. 



Why not pounce on it and get rid of it? The 

 Bembex flies fast enough to overtake it, and, small 

 as it is, the larvae would not disdain it, since they 

 eat all and every Diptera. Yet the Bembex flies in 

 terror before an enemy which one bite would hew in 

 pieces. I really feel as though I saw a cat wild 

 with terror before a mouse. The ardent pursuer of 

 Diptera is driven away by a Dipteron, and that 

 one of the smallest ! I bow before the facts without 

 any hope ot ever comprehending this reversal of 

 parts. To be able to get rid easily of a mortal 

 enemy, who is meditating the ruin of your family, 

 and who might make a feast for them — to be able, I 

 say, to do this, and not to do it when the foe is there, 

 within reach,watching you, defying you, — is the height 

 of folly in an animal. Folly, however, is not rightly 

 the word : let us rather talk of the harmony of 

 creatures, for since this wretched little Dipteron has 

 its small part to play in the great whole of things, 

 the Bembex must needs respect it and basely flee 

 before it, — otherwise long ago there would have been 

 no more Dipteron of this species in the world. 



Let us trace the history of this parasite. Among 

 Bembex nests there are found, and that frequently, 



