358 ON THE ECONOMY OF BEES. 



to produce solely male or solely female blossoms. If heat be, compara- 

 tively with the quantity of light which the plant receives, excessive, male 

 flowers only appear ; but if light be in excess, female flowers alone will 

 be produced : the experiments necessary must of course be made with 

 skill and accuracy. 



In a former communication to the Royal Society, " Upon the compara- 

 tive influence of the male and female parent upon the character of the 

 offspring, 1 ' I have inferred, from facts there stated, that the sex of the 

 offspring of some species of animals is given by the female parent. Sub- 

 sequent experience and observation have strengthened my belief in the 

 truth of this inference : but I believe the power of the female parent to 

 be rather strongly influential than positive, and that external causes 

 operate which (I have some reason to suspect) are not in all cases wholly 

 beyond the reach of human control. 



IV.-ON THE HEREDITARY INSTINCTIVE PROPENSITIES OF ANIMALS. 



[Read before the ROYAL SOCIETY, May 25th, 1837.] 



IN a communication which I had the honour many years ago to address 

 to this Society upon the Economy of Bees, I gave an opinion that families 

 of those insects, in common with those of every species of domesticated 

 animal, are to a greater or less extent governed by a power which I have 

 there called " an instinctive hereditary propensity ;"" that is, by an irre- 

 sistible propensity to do that which their predecessors of the same family 

 have been taught or constrained to do, through many successive genera- 

 tions. In that communication I stated that a young terrier whose 

 parents had been much employed in destroying polecats, and a young 

 springing spaniel whose ancestry through many generations had been 

 employed in finding woodcocks, were reared together as companions, the 

 terrier not having been permitted to see a polecat, or any other animal 

 of similar character, and the spaniel having been prevented seeing a 

 woodcock, or other kind of game ; and that the terrier evinced, as soon 

 as it perceived the scent of the polecat, very violent anger ; and as soon 

 as it saw the polecat, attacked it with the same degree of fury as its 

 parents would have done. The young spaniel, on the contrary, looked on 

 with indifference ; but it pursued the first woodcock which it ever saw 

 with joy and exultation, of which its companion, the terrier, did not in 

 any degree partake. 



