Care of the Young, in the Animal Kingdom. 161 



Dickel says: "Under normal circumstances the fer- 

 tilized mother-bee lays only fertilized eggs; it is the 

 workers, that influence and control the fate of these 

 homogeneous eggs." According to this new opinion, 

 also those eggs, which in normal bee-hives produce 

 drones, are fertilized ; and not only the differentiation 

 between queen and worker, but between queen and 

 drone, and between worker and drone, is due to 

 the influence of the salivary gland secretions of the 

 workers on the eggs previously deposited in the cells. 

 Hence, Dickel regards both queens and drones only 

 as the foundation for the development of the sexes, the 

 workers, however, as the really determining factors. 

 According to Dickel, certain salivary glands of the 

 workers contain the secretions determining the sex, 

 and the differentiation of all the castes in bee-hives 

 depends on the instinctive application of these secre- 

 tions, when the workers are licking the eggs. 



Although several biological experiments of other 

 authors seemed to confirm the theory that under nor- 

 mal conditions all the eggs in a bee-hive are fertilized, 1 

 we must add, nevertheless, that the very exact micro- 

 scopical studies of Paulke and Petrunkewitsch on the 

 existence or non-existence of spermatozoids in the 

 eggs of bees rather corroborate the old theory of 

 Dzierzon, according to which the eggs giving origin 

 to drones develop without containing any spermato- 



*) Cf. AT. Ludwig, "Neues ueber Ernaehrungs- und insbesondere ueber 

 Fortpflanzungsverhaeltnisse der Honigbiene" ("Natur und Offenb.," 

 XLIV, 1808, 12th issue, pp. 705-719), "Weiteres zur neuen Lehre ueber 

 die Geschlechtsbestimmung der Bienen" (ibid. XLV, 1899, 3d issue, pp. 

 140-148; "Weitere Ergebnisse ueber die Fortpflanzungsverhaeltnisse der 

 Biene" ("Natur und Offenbarung," 1901, 7th issue, pp. 426-430). 

 11 



