Life-cycle of Some Hymenopterous Insects 353 



are not directly fertilized, but the seminal fluid is stored up in the 

 receptacle, and this supply, once received, must serve for all sub- 

 sequent fertilizations. Dzierzon thought that the queen has 

 the power of determining at will whether an egg is to become 

 fertilized or not, and determines thereby the sex of the individual. 

 He thought that all the eggs in the ovary are alike, and the sex 

 of the individual is determined by the occurrence or absence of 

 fertilization. 



The theory of Dzierzon has been much discussed, and while* 

 its main facts have been confirmed there have not been lacking 

 those who have disputed one or another of its postulates. 



It was soon appreciated that the theory could be tested if the 

 queen of one race is fecundated by the male of another race; 

 for according to the theory the queens and workers that are 

 produced by such a queen should be hybrids, but the males 

 should belong to the pure maternal race. Thus if.a virgin Italian 

 queen is put into a hive of German bees, lacking their own queen, 

 the new queen may be fecundated by a German male. Her female 

 offspring, queens and workers, will be hybrids ; but her male 

 offspring, the drones, will be pure Italians. Dzierzon himself 

 found one instance that was an apparent exception, and so great 

 was his confidence in this test that he gave up, for a time, his 

 own theory, although later he appears to have returned to it 

 from the confirmatory results of v. Berlepsch and v. Siebold. 



This hybridizing experiment has been a source of contention 

 down to the present day, and well serves to illustrate how many 

 dangers may lurk in even a comparatively simple experiment. 

 Some of the objections to the theory may now be briefly con- 

 sidered. It appears that in some cases the drones are like the 

 hybrids, or even like the male, presumptively not their father, 

 that fertilized the queen. Thus Perez found that after intro- 

 ducing an Italian queen fertilized by a French drone into a 

 French hive, she produced 300 drones of which 5 were pure Ital- 

 ians, 83 pure French, and 66 were hybrids. The result proved, 

 he thought, that the drones were hybrids. Similar cases have 

 been described by other observers. The results seem to be 



