Of the remaining chapters, one or two have appeared in the "English
Review" or other magazines; but most of them now see the light in
English for the first time.

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.

TRANSLATOR'S NOTE.

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.