| Chapter III. The Distribution of Sexes | 5185 |
| Chapter XII. The Halicti: a Parasite | 5594 |
| Chapter VIII. Parasites | 5562 |
| Chapter IX. The Theory of Parasitism | 6442 |
| Chapter X. The Tribulations of The Mason Bee | 7197 |
| Chapter III. Another Prober (Perforator) | 6183 |
| Chapter XVI. A Parasite of The Maggot | 6625 |
