OR, MANUAI, OF THB APIARY. I15 



an examination was first made by Prof. Siebold, the ffteat 

 German anatomist, in 1843, and later by I^euckart and Leidy 

 I have myself made several such examinations. The sperma- 

 theca can easily be seen by the unaided vision, and by crush- 

 ing It on a glass slide, by compressing with a thin glass cover 

 the difference between the contained fluid in the virgin and in 

 the impregnated queen is very patent, even with a low power 

 In the latter it is more viscid and yellow, and the vesicle more 

 distended. By use of a high power, the active spermatozoa or 

 sperm-cells (Fig. SO) become visible. 



3d. Eggs in drone-cells are found by the microscopist to be 

 void of the sperm-cells, which are always found in all other 

 fresh-laid eggs. This most convincing and interesting obser- 

 vation was first made by Von Siebold, at the suggestion of 

 Berlepsch. It is quite difficult to show this. Leuckart tried 

 before Von Siebold, at Berlepsch 's apiary, but failed. I have 

 also tried to discover these sperm-cells in worker-eggs. but as 

 yet have been unsuccessful. Siebold has noted the same facts 

 in eggs of wasps. 



4th. Dr. Donhoff, of Germany, reports that, in 1855, he 

 took an egg from a drone-cell, and by artificial impregnation 

 produced a worker-bee. 



lyate investigation by Mr. Weismann, of Germany, leaves 

 no doubt of this fact of parthenogenesis in the production of 

 drone-bees. 



Parthenogenesis, in the production of males, has also been 

 found by Siebold to be true of other bees and wasps, and of 

 some of the lower moths in the production of both males and 

 females. Adler has shown that this agamic reproduction pre- 

 vails among the Chalcididae, a family of parasitic Hymenop- 

 tera, and it has long been known to characterize the cynips or 

 gall-flies ; while the great Bonnet first discovered what may be 

 noticed on any summer day all about us, even on the house- 

 plants at our very windows, that parthenogenesis is best illus- 

 trated by the aphides, or plant lice. In the fall males and 

 females appear which mate, when the females lay eggs which 

 m the spring produce only females ; these again produce only 

 females, and thus on for several generations, sometimes fifteen 

 or twenty, till with the cold of autumn come again the males 



