| Chapter I. The Terebinth Aphids. | 6615 |
| Chapter II. Experiments | 6355 |
| Chapter III. Exchanging The Nests | 4812 |
| Chapter IV. More Enquiries Into Mason Bees | 8189 |
| Chapter V. The Story of My Cats | 6334 |
| Chapter VI. The Red Ants | 9429 |
| Chapter VII. Some Reflections Upon Insect Psychology | 7989 |
| Chapter VIII. Parasites | 5889 |
| Chapter IX. The Theory of Parasitism | 6774 |
| Chapter X. The Tribulations of The Mason Bee | 7603 |
| Chapter XI. The Leucopses | 4748 |
