A Parasite of the Benibex , 293 



too small to belong to any but a parasite ; 

 besides, if any doubt remained, separate rearing 

 in a box results in Fly-grubs, followed by the 

 pupae and lastly the Miltogrammse themselves. 



The moment adopted by the Gnat is chosen 

 with great discrimination : it is the only 

 moment when she is able to accomplish her 

 designs without danger, and without useless 

 dodging about. The Wasp, half-trapped in the 

 entrance-hall, cannot see the foe so daringly 

 perched on the hind-quarters of the prey ; if she 

 suspects the parasite's presence, she cannot 

 drive her away, having no liberty of movement 

 in the narrow corridor ; lastly, in spite of all 

 the precautions which she takes to facilitate her 

 entrance, she cannot always vanish under- 

 ground with the necessary speed, the fact being 

 that the bandit is much too quick for her. This 

 indeed is the auspicious moment and the only 

 one, since prudence forbids the Fly to penetrate 

 into the cave where other Flies, far stronger 

 than herself, serve as food for the grub. Out- 

 side, in the open air, the difficulty is insurmount- 

 able, thanks to the intense vigilance of the 

 Bembex. Let us turn for a minute to the 

 arrival of the mother while her home is being 

 watched by Miltogrammse. 



A number of these Midges, greater or less 

 from time to time but usually three or four, 



