1CHAPTER 2. THE OSMIAE.
8CHAPTER 9. THE COTTON-BEES.
2CHAPTER 3. THE DISTRIBUTION OF THE SEXES.
9CHAPTER 10. THE RESIN-BEES.
3CHAPTER 4. THE MOTHER DECIDES THE SEX OF THE EGG.
10CHAPTER 11. THE POISON OF THE BEE.
4CHAPTER 5. PERMUTATIONS OF SEX.
11CHAPTER 12. THE HALICTI: A PARASITE.
5CHAPTER 6. INSTINCT AND DISCERNMENT.
12CHAPTER 13. THE HALICTI: THE PORTRESS.