xxii PARTHENOGENESIS AND SEX 499 



entirely of one sex, but which sex that is differs according to 

 other circumstances. 



Production of Sex. It is believed that a very peculiar form 

 of parthenogenesis exists in the honey-bee, and it is confidently 

 stated that the drones, or males, of that species are always pro- 

 duced from unfertilised eggs. These views are commonly called 

 the Dzierzon theory, and are widely accepted. They assume 

 that the eggs are male till fertilised, and then become female. 

 After the queen-bee is fertilised most of the spermatozoa soon 

 find their way into a small chamber, the spermatheca, near the 

 posterior orifice of the body ; it is believed that each egg may 

 be fertilised as it passes the door of this chamber, and that the 

 eggs that produce females (i.e. workers or queens) are so ferti- 

 lised, but that the eggs that produce drones are not fertilised. 

 Hence it is supposed that the sex is determined by this act of 

 fertilisation, and Cheshire has described what he calls an appa- 

 ratus for differentiating the sexes. It is also confidently stated 

 that no male honey-bee ever has a father. 



The facts we have stated as to the sexes resulting from 

 parthenogenetic reproduction in Hymenoptera generally, are 

 extremely opposed to the Dzierzon theory, in so far as this 

 relates to the production of sex. There have always been 

 entomologists l who have considered this view unsatisfactory, 

 and the observations of several recent French naturalists 2 are 

 unfavourable to the idea that the sex of an ess is determined by 



*/ 



its fertilisation. 



There can be no doubt that the queen honey-bee frequently 

 produces males parthenogenetically, and the error of the views 

 we are alluding to consists in taking the parthenogenesis to be 

 the cause of the sex of the individual. It must be recollected 

 that the laying of an unfertilised egg by a fertilised female may 

 be different physiologically from the laying of an egg by an 

 unfertilised female ; for, though both have as result an un- 

 fertilised egg, it is possible that the fertilisation of the female 

 may initiate processes that modify the sex of the eggs produced 

 by the ovaries, so that though these may produce previous to 

 fertilisation only male eggs, yet after fertilisation they may 

 produce eggs of the opposite sex or of both sexes. In other 



1 See Perez and Cameron, Tr. Nat. Hist. Soc. Glasgow, n.s. ii.1889. p. 194. 

 2 Fabre, Marchal, Nicolas. 



