| Chapter III. The Distribution of Sexes | 5101 |
| Chapter XII. The Halicti: a Parasite | 5494 |
| Chapter VIII. Parasites | 5484 |
| Chapter IX. The Theory of Parasitism | 6360 |
| Chapter X. The Tribulations of The Mason Bee | 7107 |
| Chapter III. Another Prober (Perforator) | 6090 |
| Chapter XVI. A Parasite of The Maggot | 6546 |
