| Chapter III. The Distribution of Sexes | 4828 |
| Chapter XII. The Halicti: a Parasite | 5247 |
| Chapter VIII. Parasites | 5258 |
| Chapter IX. The Theory of Parasitism | 6135 |
| Chapter X. The Tribulations of The Mason Bee | 6810 |
| Chapter III. Another Prober (Perforator) | 5862 |
| Chapter XVI. A Parasite of The Maggot | 6332 |
