| Chapter III. The Distribution of Sexes | 5048 |
| Chapter XII. The Halicti: a Parasite | 5432 |
| Chapter VIII. Parasites | 5447 |
| Chapter IX. The Theory of Parasitism | 6317 |
| Chapter X. The Tribulations of The Mason Bee | 7051 |
| Chapter III. Another Prober (Perforator) | 6046 |
| Chapter XVI. A Parasite of The Maggot | 6496 |
