| Chapter I. The Terebinth Aphids. | 6463 |
| Chapter II. Experiments | 6157 |
| Chapter III. Exchanging The Nests | 4681 |
| Chapter IV. More Enquiries Into Mason Bees | 8051 |
| Chapter V. The Story of My Cats | 6201 |
| Chapter VI. The Red Ants | 9172 |
| Chapter VII. Some Reflections Upon Insect Psychology | 7830 |
| Chapter VIII. Parasites | 5731 |
| Chapter IX. The Theory of Parasitism | 6630 |
| Chapter X. The Tribulations of The Mason Bee | 7407 |
| Chapter XI. The Leucopses | 4620 |
