iv CONTENTS. 



CHAPTER X. 



PAGB. 



THE DIODONTI ... ... 99 



CHAPTER XL 

 SOME GRAVE DIGGERS (Cerceris and Philanthus) . . 108 



CHAPTER XII. 

 , THE SPIDER RAVISHERS (Pompilus and Agenia) . .125 



CHAPTER XIII. 

 THE ENEMIES or THE ORTHOPTERA . .167 



CHAPTER XIV, 

 THE MUD- DAUBERS (Pelopaeus) . 176 



CHAPTER XV. 

 EXTRACTS FROM MARCHAL'S MONOGRAPH ON CERCERIS OR- 



NATA . . ' ',', . . ... . 200 



CHAPTER XVI. 

 ON THE SENSE OF DIRECTION IN WASPS . . . 211 



CHAPTER XVII. 

 THE STINGING HABIT IN WASPS . . 220 



CHAPTER XVIII. 

 CONCLUSIONS . . 228 



