Il6 ELEMENTS OF BIOLOGY. 



entirely upon the form of the cell into which the ovum is 

 placed, and upon the nature of the food which is supplied 

 to the larva. ■ So far there is no doubt as to the nature of 

 the phenomena which are observed. It is asserted, how- 

 ever, by Dzierzon and Siebold, that the males or drones are 

 produced by the queen from ova which she does not allow- 

 to come into contact with the semen as they pass through 

 the oviduct. This assertion is supported by the fact that if 

 the communication between the receptacle for the semen 

 and Ihe oviduct be cut off, the queen will produce nothing 

 but males. Also, in crosses between the common honey-bee 

 and the Ligurian bee, the queens and workers alone exhibit 

 any intermediate characters between the two forms, the 

 drones presenting the unmixed characters of the queen by 

 whom they were produced. 



If these observations are to be accepted as established — 

 and, upon the whole, there can be little hesitation in accepting 

 them as in the main correct — then the drones are produced 

 by a true process of parthenogenesis ; but some observers 

 maintain that the development of any given ovum into a 

 drone is really due — as in the case of the queens and 

 workers — to the special circumstances under which the 

 larva is brought up.* 



There are various other cases in which parthenogenesis 

 is said to occur, but the above will suffice to indicate the 

 general character of the phenomena in question. The 

 theories of parthenogenesis appear to be too complex to be 

 introduced here ; and there is the less to regret in their 

 omission, as naturalists have not yet definitely adopted any 



* In the case of Polistes Gallica, Von Siebold appears to have proved 

 beyond reasonable doubt that the males are produced by a process of 

 parthenogenesis. Landois, however, asserts that the eggs of insects are 

 of no sex ; that sex is only developed in the larva after its emergence 

 from the egg ; and that in each individual larva the sex is determined 

 ■wholly by the nature of the food upon which it is brought up — abundant 

 nourishment producing females, and scanty diet giving rise to males. 



