| Chapter III. The Distribution of Sexes | 5165 |
| Chapter XII. The Halicti: a Parasite | 5532 |
| Chapter VIII. Parasites | 5531 |
| Chapter IX. The Theory of Parasitism | 6408 |
| Chapter X. The Tribulations of The Mason Bee | 7183 |
| Chapter III. Another Prober (Perforator) | 6144 |
| Chapter XVI. A Parasite of The Maggot | 6593 |
