The Reproductive Processes and Parthenogenesis 187 
In 1745, Bonnet described the parthenogenetic develop¬ 
ment of plant lice and just one hundred years later Dzierzon 
announced his theory that the drone is likewise a product 
of an unfertilized egg. This later paper, published in the 
Eichstadt Bienenzeitung, was the beginning of a long and 
heated discussion in which the leading zoologists of the day 
took part. Briefly his theory was as follows: (1) the queen 
is able “at pleasure” to lay either worker or drone eggs, the 
drone eggs being deposited just as they leave the ovary 1 ; 
(2) all eggs in the ovary are eggs which would normally 
develop into males and if fertilization occurs the sex is 
changed to female. It is well to divide Dzierzon’s theory 
into these two parts for they are not equally capable of proof. 
The facts observed in the apiary on which this belief is 
based are as follows: (1) If a queen is unable to fly out to 
mate or is prevented from mating in some other way she 
usually dies (p. 70) but if she does lay eggs, as she may, 
after three or four weeks, the eggs which develop are all males ; 
(2) if when a queen becomes old her supply of spermatozoa 
is exhausted, her offspring are all males ; (3) if a colony be¬ 
comes queenless and remains so for a time, some of the 
workers may begin egg-laying and in this case too only 
males develop. The author has found that many eggs laid 
by drone-laying queens fail to hatch and, in fact, are often 
removed in a short time by the workers. This makes it 
impossible for us to accept Dzierzon’s statement that all 
eggs laid by such a queen become males and the statement 
must be modified as follows : all of those eggs laid by a drone¬ 
laying queen which develop become males. The poten¬ 
tialities of the eggs which never hatch are not known. In 
addition to the facts here stated, the theory of the partheno¬ 
genetic development of the drone is supported by investiga¬ 
tions of the phenomena of development in the egg. 
1 Onions (1912, South African fertile-worker bees. Agricultural Journal 
of the Union of S. Af., May) claims that in South African bees females are also 
produced parthenogenetically. The claim is supported by considerable 
evidence. See also Van Warmelo, 1). S., ibid., 1913, who denies this state- 
mt'iit. 
