334 PRINCIPLES OF STOCK-BREEDING. 



pollen is carried, and the loss of the power to secrete 

 wax. Thus, in acquiring the attributes peculiar to 

 the perfect reproductive female, the insect loses those 

 which distinguish the working population of the hive ; 

 and, of this departure from its usual mode of develop- 

 ment, the difference in the food with which it is sup- 

 plied appears to be the only essential condition." l 



In the development of a queen from a worker 

 larva, it does not appear to be necessary that the 

 changed conditions, as to form of cell and nutriment, 

 should be made at the earliest period of growth. 

 Dzierzon says : " I have noticed that worker larvae, so 

 far advanced that they nearly fill their cells, will still 

 be developed as perfect queens, if, before capping, 

 the cell be somewhat enlarged and widened, and the 

 larvae supplied with the appropriate pabulum." Baron 

 Berlepsch adds, " Incredible as this at first seemed, I 

 have found it, nevertheless, true." 2 



It is possible that the influence of heat and light 

 upon the sex of plants, observed by Mr. Knight, may be 

 owing to changes produced in the nutrition of the plant. 8 



Mr. Knight says : " I can at any time succeed in 

 causing several kinds of monoecious plants to produce 

 solely male or solely female blossoms. If heat be, com- 

 paratively with the quantity of light which the plant re- 

 ceives, excessive, male flowers only appear ; but, if light 

 be in excess, female flowers alone will be produced." 4 



1 Carpenter's " Comparative Physiology," p. 163. 



2 " The Dzierzon Theory," by Baron Berlepsch, p. 45. 



3 " Comparative Physiology," p. 618. 



4 " Physiological and Horticultural Papers," p. 358 ; quoted in Sci- 

 entific Farmer, 1876, p. 181. 



