128 THE EVOLUTION OF INSTINCT 



solitary forms and the highly organized social state repre- 

 sented by the hive bee. The various grades of social life 

 which these insects present have been described in a very 

 interesting little treatise by Buttel-Reepen on "Die stam- 

 msgeschichtliche Entstehung des Bienenstaates." The series 

 of forms which Buttel-Reepen describes indicates very 

 clearly that there has been a gradual specialization of 

 function in the queen from a condition in which she performed 

 all the duties of the household to one in which her functions 

 are confined practically to reproduction. A sort of division 

 of labor has come about so that the workers and the queen 

 together perform the labors formerly accomplished by 

 the queen alone. Herbert Spencer is therefore in the main 

 right in his contention that the fact that the neuters have 

 instincts not found in the queen is due to the queen's having 

 lost them in specializing in the direction of increased capacity 

 for reproduction. It is possible to maintain, therefore, that 

 the transmission of acquired characters may have moulded 

 the instincts of the worker caste up to that point in social 

 evolution at which they came to be practically sterile. 



The differences between the queen and worker are 

 occasioned by differences in food. With a diminution of 

 the food supply and a consequent arrest of development 

 of the organs of reproduction there is a suppression of the 

 reproductive instincts, but the fostering and household 

 instincts are retained. The worker, we might say, halts at 

 a phyletically older period. The queen with a richer food 

 supply develops beyond to a stage in which what might 

 have become worker characters are suppressed in the interest, 

 perhaps of greater reproductive efficiency. The condition 

 might be compared to what is found in certain parasitic 

 isopods in which the adult female after having passed through 

 active and highly organized stages of metamorphosis comes 



