| Chapter I. The Terebinth Aphids. | 4922 |
| Chapter II. Experiments | 4442 |
| Chapter III. Exchanging The Nests | 3305 |
| Chapter IV. More Enquiries Into Mason Bees | 6422 |
| Chapter V. The Story of My Cats | 4645 |
| Chapter VI. The Red Ants | 6300 |
| Chapter VII. Some Reflections Upon Insect Psychology | 6342 |
| Chapter VIII. Parasites | 4181 |
| Chapter IX. The Theory of Parasitism | 5097 |
| Chapter X. The Tribulations of The Mason Bee | 5649 |
| Chapter XI. The Leucopses | 3433 |
