| Chapter III. The Distribution of Sexes | 5312 |
| Chapter XII. The Halicti: a Parasite | 5735 |
| Chapter VIII. Parasites | 5689 |
| Chapter IX. The Theory of Parasitism | 6583 |
| Chapter X. The Tribulations of The Mason Bee | 7352 |
| Chapter III. Another Prober (Perforator) | 6327 |
| Chapter XVI. A Parasite of The Maggot | 6742 |
