| Chapter III. The Distribution of Sexes | 6302 |
| Chapter XII. The Halicti: a Parasite | 6773 |
| Chapter VIII. Parasites | 6876 |
| Chapter IX. The Theory of Parasitism | 7519 |
| Chapter X. The Tribulations of The Mason Bee | 8482 |
| Chapter III. Another Prober (Perforator) | 7337 |
| Chapter XVI. A Parasite of The Maggot | 7649 |
