| Chapter III. The Distribution of Sexes | 5767 |
| Chapter XII. The Halicti: a Parasite | 6244 |
| Chapter VIII. Parasites | 6170 |
| Chapter IX. The Theory of Parasitism | 7027 |
| Chapter X. The Tribulations of The Mason Bee | 7891 |
| Chapter III. Another Prober (Perforator) | 6816 |
| Chapter XVI. A Parasite of The Maggot | 7168 |
