| Chapter III. The Distribution of Sexes | 4600 |
| Chapter XII. The Halicti: a Parasite | 5049 |
| Chapter VIII. Parasites | 5039 |
| Chapter IX. The Theory of Parasitism | 5934 |
| Chapter X. The Tribulations of The Mason Bee | 6563 |
| Chapter III. Another Prober (Perforator) | 5661 |
| Chapter XVI. A Parasite of The Maggot | 6137 |
