| Chapter I. The Terebinth Aphids. | 7430 |
| Chapter II. Experiments | 7526 |
| Chapter III. Exchanging The Nests | 5897 |
| Chapter IV. More Enquiries Into Mason Bees | 9358 |
| Chapter V. The Story of My Cats | 7103 |
| Chapter VI. The Red Ants | 11322 |
| Chapter VII. Some Reflections Upon Insect Psychology | 8942 |
| Chapter VIII. Parasites | 6876 |
| Chapter IX. The Theory of Parasitism | 7519 |
| Chapter X. The Tribulations of The Mason Bee | 8482 |
| Chapter XI. The Leucopses | 5354 |
