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 unfertilized 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, 1 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 
