1907.] Wheeler, The Polymorphism of Ants. 61 



and taxonomy of ants can regard his attempts to trace such specialized 

 structures and instincts as those of the amazon slave-makers {Polyergus) 

 to inherited presocial acquirements as seriously invalidating Weismann's 

 argument. As I shall show in the sequel, however, Spencer presents a 

 vague adumbration of facts which have since come to light and easily dis- 

 pose of the portion of Weismann's argument relating to the amazons. 



Weismann returns to the charge in his Romanes lecture and asserts that 

 he cannot look upon Spencer's view "as a correct one in the sense implied. 

 It is certainly true that bees have it in their power to cause a larva to become 

 a queen or a worker according to the manner in which they feed it : it is 

 equally true of all animals that they reproduce only feebly or not at all when 

 badly and insufficiently nourished: and yet the poor feeding is not the 

 causa efficiens of sterility among bees but is merely the stimulus which not 

 only results in the formation of rudimentary ovaries, but at the same time 

 calls forth all the other distinctive characters of the workers. It appears to 

 me to be doubly incorrect to look upon the poor nourishment as the actual 

 cause; for such a view not only confuses the stimulus with the real cause, 

 but also fails to distinguish between an organ that becomes rudimentary 

 and one that is imperfectly developed. Moreover the fact is overlooked 

 that the ovaries of the workers are actually rudimentary organs: a great 

 proportion of their really essential parts have disappeared, while only a 

 small remnant is retained." 



Weismann goes farther and maintains that he has disproved Spencer's 

 view experimentally. He reared two lots of blow-fly larvee {Musca vomi- 

 toria), one on poor the other on abundant food, and obtained imaginal 

 flies differing greatly in size but with the reproductive as well as the other 

 organs normally developed even in the smallest individuals. The latter on 

 being well fed, mated and produced normal young. He concludes as 

 follows from this experiment: "By comparing the result of this experiment 

 with the known facts as to bees, the difference in the behavior of the two 

 organisms is made clear. In the case of bees a distinct degeneration of the 

 ovaries and various accessory organs of reproduction takes place in conse- 

 quence of poor nourishment; while in flies the whole reproductive apparatus 

 is formed quite as perfectly when the nourishment of the larva is deficient 

 as when it is ample. There is even no delay in the maturing of the eggs, 

 as shown by the fact that the first batch was laid at exactly the same time 

 as in the case of the flies arising from normally fed larvae. 



"It might, however, be said that flies and bees are very different organ- 

 isms, and therefore react differently to external influences. This is quite 

 true, and is exactly what I wish to be acknowledged. My experiments 

 with the flies were merely meant to show that all insects, even though they 



