HO THE BIOLOGY OF INSECTS 



and a female's thirty-two chromosomes. F. Meves (1901) 

 and others have shown that in the female egg maturation 

 pursues its usual course so that the ripe egg has only six- 

 teen. In spermatogenesis, however, the first maturation 

 division is abortive, a small cytoplasmic body being divided 

 off from the spermatocyte which retains all sixteen chromo- 

 somes in its nucleus. Then in the succeeding division 

 these are, as usual, split so that each of the two resulting 

 spermatids has sixteen chromosomes. Hence it follows 

 that an unfertilised egg (with sixteen chromosomes) will 

 develop into a male or " drone " bee, while a fertihsed 

 egg (with thirty-two chromosomes) will develop into a 

 female bee, either a *' queen "or a '' worker " ; which 

 of these two latter alternative results will be produced 

 depends upon the treatment and feeding of the larva, a 

 striking illustration of the co-operation of the factors of 

 heredity and environment — of " nature " and " nurture " 

 — in bringing about the final result of the reproductive 

 process. 



The origin of females from fertilised and of males from 

 virgin eggs has long been recognised as the general rule 

 among the bees, wasps, and their allies. Some careful 

 breeding experiments by W. Newell (191 5), who crossed 

 yellow Italian bees with members of a grey race, afford 

 confirmation of the accepted view. When yellow queens 

 were mated with grey drones all the offspring were yellow, 

 the colour factor for this being dominant to that for grey ; 

 but when grey females were mated with yellow drones the 

 workers were yellow but the drones were grey ; these latter 

 clearly had no inheritance through a male parent. But 

 from the eggs of hybrid yellow females either grey or yellow 

 drones might be produced. Statements have, however, 

 often been made that drone bees may be developed from 

 fertilised eggs by special feeding of the larvae ; if such 

 statements really represent the facts, cases of intersexuality 

 (PP- i33~5) niight be supposed. R. W. Jack (19 16) has 

 brought forward evidence that cannot be lightly set aside 

 for the occasional development of worker bees from the 



