EIGHTH ANNUAL YEAR BOOK— PART X. 677 



eggs. As we have said, workers as well as queens are females, but they 

 are incapable of mating, and the eggs laid by them produce nothing 

 but drones. 



This statement of the theory of parthenogenesis or the "Theory of 

 Dzierzon," as it is commonly called, differs from the usual statements of 

 the theory that find place in the books on apiculture. The Theory of 

 Dzierzon can be divided into two parts. (1) Drone eggs are unfertilized, 

 while female eggs are fertilized. To this part all observations lead us to 

 subscribe. (2) All the eggs in the ovary of the queen are male eggs and 

 the fertilization of the egg changes its sex and it becomes female. 



The latter portion of the theory is not founded on actual observation 

 but on logic only, and not on sound logic either. Let us state the theory 

 in a different manner. Male eggs are unfertilized and female eggs are 

 fertilized. As far as we can see this is the only difference between them, 

 and since we can see no other difference this must be the thing which 

 changes the sex. Is it not clear that the conclusion does not necessarily 

 follow, for is it not possible that there is some difference between these 

 eggs not yet observed, which is the all-determining factor, rather than 

 that fertilization is? 



Fertilization may have nothing to do with sex-determination: (1) 

 Nowhere else is the animal kingdom, except in animals exhibiting parthe- 

 nogenesis, is it claimed that fertilization has any influence on sex. (2) 

 The ants, which were formerly considered to be similar to the bee in 

 their parthenogenesis, sometimes, according to some recent work, have 

 females produced from unfertilized eggs. (3) In the vast majority of 

 cases where the problem of sex has been investigated there is strong evi- 

 dence that the sex of the offspring is determined before the egg leaves 

 the ovary. (4) Certain observations made during the past two summers 

 tend to show that there is some other difference between male and fe- 

 male eggs. 



In studying the problem of parthenogenesis I was struck by the illogical 

 conclusion concerning sex, and to test the theory spent some considerable 

 time in observations on the subject. I found that many of the eggs laid 

 by a drone-laying queen never develop at all. According to the theory 

 as propounded by Dzierzon and his followers, all the eggs in the ovary 

 are male and if they are unfertilized all should develop and become 

 drones. But all do not develop. I have observed drone-laying queens in 

 one-frame observation hives, and in eight-frame hives, and in all my ob- 

 servations there were always a considerable number of eggs which dried 

 up and did not develop. Of course, all that did develop became drones. 



From these facts it is possible that the sex may be determined in the 

 ovaries before fertilization. Male eggs do not require fertilization, and 

 therefore can develop when laid by a drone-layer, but the female eggs of 

 a drone-layer require fertilization, and since they do not get it they die. 

 I am as yet unable to give an exact ratio between the number of eggs 

 which develop and those that do not, owing to difBculties in observation, 

 but of the fact that some do not develop I am sure. 



Of course, it will be recognized that this is but a theory with a 

 somewhat small basis of fact, but the facts observed seem to me to be 

 enough to throw doubt on the second part of the Dzierzon theory — that 



