TABLE OF CONTENTS xvii 



Formation of the imago in Chironomus 671 



Formation of the imago in Muscidae 673 



b. Development of the internal organs of the imago .... 678 



The hypodermis 678 



The muscles 680 



The digestive canal 681 



The tracheal system 683 



The nervous system 684 



The fat-body 685 



Definitive fate of the leucocytes 685 



The postembryonic changes and imaginal buds in the Pupipara 



(Melopliagus) 686 



c. General summary 687 



HYPERMETAMORPHISM 688 



Si" MM ART OF THE FACTS AND SUGGESTIONS AS TO THE CAUSES OF META- 



MORPHISM 705 



Theoretical conclusions ; causes of metamorphosis .... 708 



