| Chapter III. The Distribution of Sexes | 4500 |
| Chapter XII. The Halicti: a Parasite | 4957 |
| Chapter VIII. Parasites | 4935 |
| Chapter IX. The Theory of Parasitism | 5841 |
| Chapter X. The Tribulations of The Mason Bee | 6453 |
| Chapter III. Another Prober (Perforator) | 5565 |
| Chapter XVI. A Parasite of The Maggot | 6051 |
