| Chapter III. The Distribution of Sexes | 4437 |
| Chapter XII. The Halicti: a Parasite | 4893 |
| Chapter VIII. Parasites | 4876 |
| Chapter IX. The Theory of Parasitism | 5783 |
| Chapter X. The Tribulations of The Mason Bee | 6373 |
| Chapter III. Another Prober (Perforator) | 5510 |
| Chapter XVI. A Parasite of The Maggot | 5992 |
