30 MANUAL OF ZOOLOGY. 



certain period of the year the queen leaves the hive, accom- 

 panied by the drones (or males), and takes what is known as 

 her ' nuptial flight ' through the air. In this flight she is 

 impregnated by the males, and it is immaterial whether this 

 act occurs once in the life of the qneen, or several times, as 

 asserted by some. Be this as it may, the queen, in virtue of 

 this single impregnation, is enabled to produce fresh in- 

 dividuals for a lengthened period, the semen of the males 

 being stored up in a receptacle, which communicates by a 

 tube with the oviduct, from which it can be shut off at will. 

 The ova which are to produce workers (undeveloped females) 

 and queens (fertile females) are fertilised on their passage 

 through the oviduct, the semen being allowed to escape into 

 the oviduct for this purpose. The subsequent development of 

 these fecundated ova into workers or queens depends entirely 

 upon the form of the cell into which the ovurn 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, however, 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 the oviduct be cut off, the 

 queen will produce nothing but males. Also, in crosses be- 

 tween the common honey-bee and the Ligurian bee, the queens 

 and workers alone exhibit any intermediate characters be- 

 tween the two forms, the drones presenting the unmixed 

 character of the queen by whom they were produced. 



If these observations are to be accepted as established, 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 par- 

 thenogenesis 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 one explanation of the 

 phenomena to the exclusion of the rest. 



Fir.4 Law of Quatrefages. From the phenomena of asexual 

 reproduction in all its forms, M. de Quatrefages has deduced 

 the following generalisation : 



' The formation of new individuals may take place, in some 



