| Chapter III. The Distribution of Sexes | 6272 |
| Chapter XII. The Halicti: a Parasite | 6738 |
| Chapter VIII. Parasites | 6806 |
| Chapter IX. The Theory of Parasitism | 7481 |
| Chapter X. The Tribulations of The Mason Bee | 8441 |
| Chapter III. Another Prober (Perforator) | 7303 |
| Chapter XVI. A Parasite of The Maggot | 7621 |
