INTRODUCTION. 7 



I believe I ought to give some information as to the way in 

 which I have been induced to take part in this active movement 

 of the Apiarians, as reference is made hereafter to a new theory 

 of reproduction applying to the Bees, the defence of which I 

 have undertaken, not however from a preconceived opinion forced 

 upon me from without, but from an internal conviction springing 

 from the course of my own investigations and observations. 

 From the following pages the reader will understand how the 

 investigation of the history of reproduction in Insects necessarily 

 led me to the natural history of the Bees. 



Probably within the last few years no branch of the history 

 of animals has been enriched by new discoveries, and the am- 

 plification and completion of old observations, in so high a 

 degree as the theory of animal reproduction. A mass of facts 

 which were in direct contradiction to the theoretical laws so 

 long established as the rules for the propagation of animals, and 

 which previously had scarcely any value but their curiosity, 

 have been united by the piercing eye of Steenstrup under the 

 name of Alternation of Generations* to form a law, w r hich is 

 now found by naturalists to prevail in all directions. There was 

 previously a long series of remarkable observations, against the 

 correctness of which, as they stood in contradiction to the laws 

 of reproduction previously adopted as the rule, doubts might 

 willingly have been raised, if the stamp of truth had not been , 

 impressed upon them by the credibility of their observers. 

 From many of these observations, over which a naturalist here 

 and there was every now and then shaking his head in incre- 

 dulity f> all doubt has been now cleared away by the recognition 



* Steenstrup, Ueber den Generationswechsel, Copenhagen, 1842. 



f This negation of the processes connected with the alternation of genera- 

 tions is expressed even in the most recent times, in the views by which Ehren- 

 berg and Diesing explain the nature of the Cercarice. Although direct 

 observations and the most careful investigations have shown that these re- 

 markable asexual creatures are not perfect animals, but belong, as larvae, in 

 the developmental series of certain Trematode worms, Ehrenberg sticks stead- 

 fastly to his opinion, that the Cercarice only present a distant similarity to 

 the Trematoda (see the Bericht iiber die zur Bekanntmachung geeigneten Ver- 

 handlungen der Akad. der Wiss. zu Berlin a. d. J. 1851, p. 77o"), and re- 

 proaches Steenstrup with having allowed himself to be misled into tin 



