| Chapter III. The Distribution of Sexes | 3202 |
| Chapter XII. The Halicti: a Parasite | 3566 |
| Chapter VIII. Parasites | 3596 |
| Chapter IX. The Theory of Parasitism | 4349 |
| Chapter X. The Tribulations of The Mason Bee | 4987 |
| Chapter III. Another Prober (Perforator) | 4455 |
| Chapter XVI. A Parasite of The Maggot | 4758 |
