| Chapter I. The Terebinth Aphids. | 7116 |
| Chapter II. Experiments | 7067 |
| Chapter III. Exchanging The Nests | 5475 |
| Chapter IV. More Enquiries Into Mason Bees | 8975 |
| Chapter V. The Story of My Cats | 6829 |
| Chapter VI. The Red Ants | 10509 |
| Chapter VII. Some Reflections Upon Insect Psychology | 8634 |
| Chapter VIII. Parasites | 6470 |
| Chapter IX. The Theory of Parasitism | 7235 |
| Chapter X. The Tribulations of The Mason Bee | 8155 |
| Chapter XI. The Leucopses | 5186 |
