| Chapter I. The Terebinth Aphids. | 1148 |
| Chapter II. Experiments | 1060 |
| Chapter III. Exchanging The Nests | 659 |
| Chapter IV. More Enquiries Into Mason Bees | 1312 |
| Chapter V. The Story of My Cats | 1163 |
| Chapter VI. The Red Ants | 960 |
| Chapter VII. Some Reflections Upon Insect Psychology | 1453 |
| Chapter VIII. Parasites | 752 |
| Chapter IX. The Theory of Parasitism | 798 |
| Chapter X. The Tribulations of The Mason Bee | 1202 |
| Chapter XI. The Leucopses | 448 |
