206 THE LIFE AND LOVE OF THE INSECT 



precaution when the box is occupied by an Halictus in 

 course of metamorphosis, becomes a screaming absurdity 

 when the Dipteron has passed that way. Instinct does 

 not hesitate in the face of this incongruity : it seals up 

 emptiness. I say, emptiness, because the crafty maggot 

 hastens to decamp the instant that the victuals are 

 consumed, as though it foresaw an insuperable obstacle 

 for the coming Fly : it quits the cell before the Hymenop- 

 teron closes it. 



To rascally guile the parasite adds prudence. All, 

 until there is none of them left, abandon the clay homes 

 which would be their undoing, once the entrance was 

 plugged up. The earthy retreat, so grateful to the tender 

 skin, thanks to its polished coating, so free from humidity, 

 thanks to its waterproof glaze, ought, one would think, 

 to make an excellent waiting-place. The maggots will 

 have none of it. Lest they should find themselves walled 

 in when they become frail Gnats, they go away and dis- 

 perse in the neighbourhood of the ascending pit. 



My digging operations, in fact, always reveal the pupae 

 outside the cells, never inside. I find them enshrined, one 

 by one, in the body of the clayey earth, in a narrow niche 

 which the emigrant worm has contrived to make for 

 itself. Next spring, when the hour comes for leaving, the 

 adult insect has but to creep through the rubbish, which is 

 easy work. 



Another and no less imperative reason compels this 

 change of abode on the parasite's part. In July, a second 

 generation of the Halictus is procreated. The Dipteron, 

 reduced, on her side, to a single brood, remains in the 

 pupa state and awaits the spring of the following year 

 before effecting her transformation. The honey -gatherer 

 resumes her work in the natal hamlet ; she avails herself 



