| Chapter III. The Distribution of Sexes | 6037 |
| Chapter XII. The Halicti: a Parasite | 6533 |
| Chapter VIII. Parasites | 6518 |
| Chapter IX. The Theory of Parasitism | 7260 |
| Chapter X. The Tribulations of The Mason Bee | 8176 |
| Chapter III. Another Prober (Perforator) | 7073 |
| Chapter XVI. A Parasite of The Maggot | 7428 |
