| Chapter III. The Distribution of Sexes | 6013 |
| Chapter XII. The Halicti: a Parasite | 6507 |
| Chapter VIII. Parasites | 6466 |
| Chapter IX. The Theory of Parasitism | 7234 |
| Chapter X. The Tribulations of The Mason Bee | 8153 |
| Chapter III. Another Prober (Perforator) | 7051 |
| Chapter XVI. A Parasite of The Maggot | 7410 |
