| Chapter III. The Distribution of Sexes | 800 |
| Chapter XII. The Halicti: a Parasite | 895 |
| Chapter VIII. Parasites | 752 |
| Chapter IX. The Theory of Parasitism | 798 |
| Chapter X. The Tribulations of The Mason Bee | 1202 |
| Chapter III. Another Prober (Perforator) | 1031 |
| Chapter XVI. A Parasite of The Maggot | 1205 |
