310 THE WONDERS OF INSTINCT 



quite softly, not of any wounds, but of anemia, even as a 

 lamp goes out when the oil comes to an end. And it 

 has to be. The living caterpillar, capable of feeding 

 himself and forming blood, is a necessity for the welfare 

 of the grubs; he has to last about a month, until the 

 Microgaster's offspring have achieved their full growth. 

 The two calendars synchronize in a remarkable way. 

 When the caterpillar leaves off eating and makes his 

 preparations for the metamorphosis, the parasites are 

 ripe for the exodus. The bottle dries up when the 

 drinkers cease to need it ; but until that moment it must 

 remain more or less well-filled, although becoming limper 

 daily. It is important, therefore, that the caterpillar's 

 existence be not endangered by wounds which, even 

 though very tiny, would stop the working of the blood- 

 fountains. With this intent, the drainers of the bottle 

 are, in a manner of speaking, muzzled ; they have by way 

 of a mouth a pore that sucks without bruising. 



The dying caterpillar continues to lay the silk of his 

 carpet with a slow oscillation of the head. The moment 

 now comes for the parasites to emerge. This happens 

 in June and generally at nightfall. A breach is made 

 on the ventral surface or else in the sides, never on the 

 back: one breach only, contrived at a point of minor 

 resistance, at the junction of two segments; for it is 

 bound to be a toilsome business, in the absence of a set 

 of filing-tools. Perhaps the grubs take one another's 

 places at the point attacked and come by turns to work 

 at it with a kiss. 



In one short spell, the whole tribe issues through this 



