| Chapter III. The Distribution of Sexes | 4109 |
| Chapter XII. The Halicti: a Parasite | 4589 |
| Chapter VIII. Parasites | 4553 |
| Chapter IX. The Theory of Parasitism | 5481 |
| Chapter X. The Tribulations of The Mason Bee | 6022 |
| Chapter III. Another Prober (Perforator) | 5249 |
| Chapter XVI. A Parasite of The Maggot | 5691 |
