viii CONTENTS. 



CHAPTER PAGE 



SEC. 3. The Exo-skeleton of the Proboscis - 127 



a. General Morphology . - 127 



b. The Sclerites and Morphology of the Proboscis of 



the Blow-Fly - 134 



c. The Proboscis of the Immature Imago - - 148 



d. Comparative Anatomy of the Proboscis in the 



Diptera - - - 149 



SEC. 4. The Thoracic Exo-skeleton - - 1 54 



<i. General Morphology - 154 



b. General Description of the Thoracic Skeleton of 



the Blow-Fly - 166 



c. The Sclerites of the Thoracic Skeleton 171 



d. Details of the Exo-skeleton of the Legs - 190 



e. The Wings and Mechanism of Flight - 198 

 SEC. 5. The Exo-skeleton of the Abdomen - 209 



a. General Morphology - 209 



b. The Abdominal Skeleton of the Blow-Fly - - 210 

 APPENDIX TO CHAPTER V. Methods of Study - 211 



VI. THE TOPOGRAPHICAL ANATOMY OF THE MUSCLES AND 



VISCERA OF THE IMAGO - 215 



VII. THE EMBRYOLOGY OF THE BLOW-FLY IN THE EGG - - 230 

 SEC. i. Early Changes in the Ovum subsequent to Fertilization 



and Formation of the Blastoderm - 230 



2. Formation of the Membranes and Primitive Band - 241 

 3. Origin of the Archenteron, Somatopleure and Ccelomic 



Sacs - - 247 

 ,, 4. The Dorsal Organ of Kowalevski - 254 

 5. The Nymphoid Stage of the Embryo, and its Con- 

 version into the Larva 257 

 VIII. GENERAL ANATOMY AND HISTOLOGY OF THE BLOW-FLY - 262 

 SEC. i. Cells and Nuclei - 264 

 2. The Parablastic Tissues 270 

 3. Epithelia 277 

 4. Muscles and Nerves - 282 



a. The Muscles 282 



b. The Nerves - 288 

 IX. THE DEVELOPMENT OF THE NYMPH IN THE PUPA - - 292 



SEC. i. Formation of the Pronymph from the Larva - 296 



a. Histolysis of the Larval Muscles - - 297 



b. The Histolysis of the Hypodermis, and the For- 



mation of the Paraderm - - 299 



c. Relation of the Imaginal Discs to the Paraderm - 303 



d. The Contraction of the Paraderm and Evolution of 



the Discs - - 305 



