For long people believed the plant louse truly androgynous. Réaumur 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 the male and female, and noted even the genital ardour of this sticking leaf-louse, this milch-cow of the ants. Parthenogenesis is a sign-post. Nothing more clearly demonstrates the importance of the male or the precision of his function. The female appears to be the whole show, without the male she is nothing. She is the machine and has to be wound up to go. The male is merely the key. People have tried to obtain fecundation by false keys. Eggs of sea-anemones, and star-fish have been hatched by contact with exciting chemicals, acids, alkalines, sugar, salt, alcohol, ether, chloroform, strychnine gas, carbonic acid. But one has never been able to bring these scientific larvæ to maturity, and everything leads one to believe that if one succeeded, and that if these artificial beings were capable of reproduction, it would be but for a limited period. This provoked parthenogenesis is neither more nor less interesting than the normal. It is doubtless abnormal, but abnormal parthenogenesis is not infrequent in nature; eggs of the bombyx, of star-fish, and of frogs, hatch sometimes without fecundation, and very probably because they have accidentally come up against the very stimulant which the excellent experimenters have lavished on them. Whether sperm acts as an "excitant" or as fecundator, the action is no easier to understand by one label than by another. The queen bee lays both fecundated and non-fecundated eggs; the first hatch female, the second invariably male, here the male element would seem to be the product of parthenogenesis and the female to require previous fecundation. In contrast, among plant-lice, the generations of female continue for nearly two years. There is an order in these things, as in all things, but it is not yet apparent; one notes only, that however long and varied be the parthenogenetic period, it is limited somewhere by the necessity of the female principle being united with the male principle. After all, hereditary fecundation is no more extraordinary than particular fecundation, it is a mode of perpetuating life which the exercise of one's reason should make one consider as perfectly normal.