| Chapter III. The Distribution of Sexes | 5792 |
| Chapter XII. The Halicti: a Parasite | 6268 |
| Chapter VIII. Parasites | 6185 |
| Chapter IX. The Theory of Parasitism | 7039 |
| Chapter X. The Tribulations of The Mason Bee | 7909 |
| Chapter III. Another Prober (Perforator) | 6834 |
| Chapter XVI. A Parasite of The Maggot | 7187 |
