76 PARTHENOGENESIS 



by the artificial impregnation of the Bee's eggs. But this mode 

 of proof was necessarily given up again at once as impracti- 

 cable, for whoever submits the eggs of Bees to a close examina- 

 tion will immediately see that these eggs, from their extreme 

 delicacy, are quite unfitted for such experiments. There 

 would be no possibility of extracting mature eggs uninjured 

 from the ovaries, in order to transfer them either unfecundated 

 or artificially impregnated into cells, to be taken care of by the 

 Bees ; nor would these delicate eggs bear, without injury, 

 the contact of a brush, however fine, moistened with the semen 

 of male Bees, as would be required for artificial impregna- 

 tion. Leuckart proposed* to employ eggs which had already 

 been laid as drone-eggs in drone-cells, and to fertilize them arti- 

 ficially afterwards, in order in this way to decide the question, 

 whether we should succeed by artificial impregnation in deve- 

 loping such eggs into workers or queens. He called atten- 

 tion, however, at the same time, to the difficulties which are 

 opposed to the success of this experiment. Leuckart justly 

 pointed out, that only very fresh and newly deposited drone-eggs 

 should be made use of for artificial fecundation ; for as soon as 

 the thin albuminous coating, with which the eggs of insects are 

 laid, becomes dry, which certainly takes place very quickly on 

 deposited eggs, the semen employed for artificial impregnation 

 can no longer penetrate through the pores of the egg-shell into 

 the interior of the egg, by which means alone, as will be shown 

 hereafter, the fertilization of the eggs of insects can be com- 

 pleted. From the importance of the object which would be 

 attained by these experiments, difficult as they are to carry out, 

 1 heartily join in Leuckart' s wish, that such experiments should 

 be undertaken by many hands ; perhaps one or other of the ex- 

 perimenters would be so fortunate, by the concurrence of several 

 favourable accidents, as to attain what from Dzierzon's theory 

 must a priori be expected as the result. From the preceding 

 statements it follows that the artificial impregnation of Bees' eggs 

 could not as yet be employed in favour of Dzierzon's theory. 



Very different hopes were awakened in this respect, when we 

 became acquainted with the existence and office of the micropyle 



* See the Bienenzeituny, 1855, p. 206. 



