| Chapter I. The Terebinth Aphids. | 7317 |
| Chapter II. Experiments | 7313 |
| Chapter III. Exchanging The Nests | 5746 |
| Chapter IV. More Enquiries Into Mason Bees | 9243 |
| Chapter V. The Story of My Cats | 7009 |
| Chapter VI. The Red Ants | 10910 |
| Chapter VII. Some Reflections Upon Insect Psychology | 8809 |
| Chapter VIII. Parasites | 6691 |
| Chapter IX. The Theory of Parasitism | 7400 |
| Chapter X. The Tribulations of The Mason Bee | 8334 |
| Chapter XI. The Leucopses | 5287 |
