I have once more, as in the case of "The Mason-bees," to thank Miss Frances Rodwell for the help which she has given me in the work of translation and research; and I am also grateful for much kind assistance received from the staff of the Natural History Museum and from Mr. Geoffrey Meade-Waldo in particular.

ALEXANDER TEIXEIRA DE MATTOS.

Chelsea, 1915.


Contents

[ CHAPTER 1. ] BRAMBLE-DWELLERS.
[ CHAPTER 2. ] THE OSMIAE.
[ CHAPTER 3. ] THE DISTRIBUTION OF THE SEXES.
[ CHAPTER 4. ] THE MOTHER DECIDES THE SEX OF THE EGG.
[ CHAPTER 5. ] PERMUTATIONS OF SEX.
[ CHAPTER 6. ] INSTINCT AND DISCERNMENT.
[ CHAPTER 7. ] ECONOMY OF ENERGY.
[ CHAPTER 8. ] THE LEAF-CUTTERS.
[ CHAPTER 9. ] THE COTTON-BEES.
[ CHAPTER 10. ] THE RESIN-BEES.
[ CHAPTER 11. ] THE POISON OF THE BEE.
[ CHAPTER 12. ] THE HALICTI: A PARASITE.
[ CHAPTER 13. ] THE HALICTI: THE PORTRESS.
[ CHAPTER 14. ] THE HALICTI: PARTHENOGENESIS.