TABLE OF CONTENTS. xin 



PAGE 



III. The Egg 70 



i. Description. 2. Fertilization and Its Relation to Sex. 3. 

 Development. 



IV. The Larva 72 



i. Description. 2. Feeding. 3. Internal Structure. 



V. Pupation 76 



VI. Coloration of the Callows 79 



VII. Length of Developmental Periods 80 



VIII. Longevity of Adult Ants . 81 



IX. Resistance of Ants to Noxious Influences 83 



CHAPTER VI. 



4 



POLYMORPHISM. 



I. Definition of the Term 86 



II. Extent and Character of Polymorphism among Insects. ... 87 



III. The Phylogenetic Origin and Development of Polymor- 



phism in Hymenoptera 90 



i. The Views of Various Authors. 2. Phylogeny of the Phases 

 Known among Ants. 



IV. The Development of the Worker the Real Problem of Poly- 



morphism in Ants 91 



i. Weismann's Theory of Predetermining Units. 2. Spencer's 

 Theory of Trophic Epigenesis. 3. Emery's Theory of Pre- 

 disposition. 



V. The Three Aspects of the Problem 102 



i. The Physiological and Ontogenic. 2. The Ethological and 

 Phylogenetic. 3. The Psychological. 



VI. The Physiological and Ontogenic Method of Explaining the 



Development of the Worker 103 



i. The Advantage of the Physiological over the Embryological 

 Method. 2. The Two General Objections to the Physiolog- 

 ical Explanation. 3. Inferences which tend to show that 

 Qualitative Feeding is not Responsible for the Worker Type. 

 4. The Relation of Underfeeding to the Ontogeny of the 

 Worker and Related Types. 5. Conclusion. 



