PHILOSOPHY OF LOVE 



They couple and produce females parthenogenetically en- 

 dowed. This has been for long time a mystery, it is 

 still a mystery, for side by side with normal partheno- 

 genesis there is irregular parthenogenesis, there are cases 

 where non-fecundated eggs behave exactly as fecundated 

 eggs, without anyone's knowing why. 



The virgin-begotten cycle of plant-lice is famous, that 

 of wheel-animals not less entertaining. The males, 

 smaller than the females, live but two or three days, 

 couple and die. The fecundated females lay eggs whence 

 come nothing but females, unless the eggs are subjected 

 to a temperature above 18 degrees (centigrade); above 

 that the eggs hatch out males. Between the periods of 

 coupling there are long stretches of virgin-birth, nothing 

 but females producing females, until the temperature per- 

 mits a male hatch. In two years the plant louse runs 

 through ten or twelve parthenogeneses ; in July of the 

 second year, there appear winged individuals, these are 

 still female, but double size, and they lay two sets of eggs, 

 whereof the smaller hatch male (the male is three or four 

 times smaller than the female), the larger eggs hatch 

 female; there is coupling and the cycle begins again. 



For long people believed the plant louse truly andro- 

 gynous. Reaumur and Bonnet, having seen isolated 

 plant-lice reproduce themselves were convinced of this, 

 when Trembley, a man of genius, celebrated also for his 

 observations of hydra, threw out the idea: Who knows 

 whether a coupling of these lice does not fecundate them 

 for several generations? He had discovered the basis of 

 parthenogenesis. Facts upheld him. Bonnet described 

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