| Chapter I. The Terebinth Aphids. | 7134 |
| Chapter II. Experiments | 7091 |
| Chapter III. Exchanging The Nests | 5539 |
| Chapter IV. More Enquiries Into Mason Bees | 8994 |
| Chapter V. The Story of My Cats | 6841 |
| Chapter VI. The Red Ants | 10557 |
| Chapter VII. Some Reflections Upon Insect Psychology | 8650 |
| Chapter VIII. Parasites | 6516 |
| Chapter IX. The Theory of Parasitism | 7258 |
| Chapter X. The Tribulations of The Mason Bee | 8176 |
| Chapter XI. The Leucopses | 5193 |
