| Chapter III. The Distribution of Sexes | 5095 |
| Chapter XII. The Halicti: a Parasite | 5468 |
| Chapter VIII. Parasites | 5476 |
| Chapter IX. The Theory of Parasitism | 6351 |
| Chapter X. The Tribulations of The Mason Bee | 7098 |
| Chapter III. Another Prober (Perforator) | 6081 |
| Chapter XVI. A Parasite of The Maggot | 6529 |
