The Reproductive Processes and Parthenogenesis 189 



when the side walls are only started and since drone eggs 

 are often laid in worker cells, this simple explanation cannot 

 be accepted. 



From the various phenomena observed in connection with 

 parthenogenetic development, it appears that fertilization 

 of the egg serves two purposes ; it brings to the egg the 

 hereditary characters of the male parent and also stimulates 

 the egg cell to develop by cell division. If development can 

 occur without this stimulation, the resulting individual con- 

 tains the hereditary characters from one parent only. It 

 should perhaps be mentioned that in plant lice both males 

 and females sometimes develop from unfertilized eggs while in 

 certain Lepidoptera only females develop from unfertilized 

 eggs. The male sex is not a necessary result of partheno- 

 genetic development. 



The theory that drones develop from unfertiUzed eggs 

 has not been accepted without protest. From the begin- 

 ning, it has been assailed by the publication of evidence and 

 arguments which were supposed to contradict the theory. 

 In the author's paper, to which reference has been made, 

 the various contrary views are outlined and the interested 

 reader is referred to this paper for references to the literature 

 on the subject up to the date of publication (1903). Of 

 recent critics, none is so insistent as Dickel, a German bee- 

 keeper, who claims that fertile queens cannot lay unfer- 

 tilized eggs and that sex is determined by secretions of the 

 nurse bees. These fantastic theories with others of a similar 

 character have been adequately overthrown by Dickel's 

 critics and need not be discussed at length here. 



Practical applications. 



The development of males from unfertilized eggs is a fact 

 of importance in various phases of apiary work. If, for 

 example, an Italian queen mates with a black drone, the 

 workers and queen offspring are hybrids,^ while the drone 



1 Exception is sometimes taken to the use of the word hybrid as applied 

 to a cross of two races, in which sense it is used by beekeepers. This 



