128 FECUNDATION OF ANTS. 
main to keep up the population. We 
shall now see in what manner nature 
guards against that desertion of females 
with which the ant-hill is threatened. 
In speaking of the swarms of ants, I 
avoided making an observation, which re- 
quired some developement, and which 
comes in now in its proper place. It is 
this: that the-union of the sexes does 
not always take place at a distance from 
the ant-hill. It ordinarily happens, that 
the males, before setting off, leave in the 
ant-hill afew impregnated females. The 
labourers, as if fully aware of the impor- 
tance of preserving females capable of 
maintaining the population of the repub- 
lic, carefully retain these valuable depo- 
sitaries of a future generation. Of this 
remarkable feature of their foresight or 
instinct, I have been a frequent witness ; 
not only on natural ant-hills, but even in 
my glass apparatus, where I observed it 
under more detail]. I removed the bell- 
glass which was placed over them, be- 
cause I perceived it concentrated the 
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