| Chapter I. The Terebinth Aphids. | 6105 |
| Chapter II. Experiments | 5756 |
| Chapter III. Exchanging The Nests | 4334 |
| Chapter IV. More Enquiries Into Mason Bees | 7649 |
| Chapter V. The Story of My Cats | 5842 |
| Chapter VI. The Red Ants | 8527 |
| Chapter VII. Some Reflections Upon Insect Psychology | 7464 |
| Chapter VIII. Parasites | 5407 |
| Chapter IX. The Theory of Parasitism | 6275 |
| Chapter X. The Tribulations of The Mason Bee | 6993 |
| Chapter XI. The Leucopses | 4332 |
