History of the Theory of Heredity. 61 



Lenckart, Berlopsch, and others have shown, by micro- 

 scopic examination, that in such cases the receptacnlum- 

 seminis is empty, and the queen is a virgin. In such 

 cases, as well as in hives, where the receptaculum-semi- 

 nis of the queen has been exhausted by old age, or has 

 been removed, it is well known to bee-cultivators that 

 only drones are produced, while eggs destined to give 

 rise to females, to workers or perfect queens, are pro- 

 duced only by queens which have been impregnated and 

 have some of the male fluid in the receptacle. This 

 fact, considered in connection with the fact that the 

 eggs laid by Avorkers produce only drones, indicates that 

 the drone eggs laid by an impregnated queen are not 

 fertilized; and Siebold has found active spermatozoa on, 

 newly laid worker-eggs, but has failed to find them on 

 drone-eggs. We are, therefore, compelled to believe that 

 the queen is able to lay both fertilized and parthenoge- 

 netic eggs. It is stated that when a queen of the com- 

 mon German variety is crossed with a drone of the Ital- 

 ian bee she produces hybrid workers, Avhile her male 

 offspring are all pure German bees. 



In certaiu Lepidoptera, as in the bees, parthenogene- 

 sis seems to be normal, and it has been observed in Sole- 

 nobia and Psyche by a great number of ancient and mod- 

 ern naturalists, including Schrank, Reaumer, Pallas, De 

 Geer, Scriba, Speyer, Reutti, Siebold, Leuckart, Hof- 

 mann, and others. Their observations show — 1st, that 

 tlie wino'less female is abundant and widelv distributed at 

 all seasons, while the winged males are seldom met with, 

 and are found only in certain restricted localities; 2(1, 

 that there is only one form of female; those which unite 

 with the male, as well as those who do not, have perfect 

 reproductive organs which resemble those of other but- 

 terflies. Parthenogenesis is the rule, and the females 



