| Chapter III. The Distribution of Sexes | 1293 |
| Chapter XII. The Halicti: a Parasite | 1444 |
| Chapter VIII. Parasites | 1217 |
| Chapter IX. The Theory of Parasitism | 1317 |
| Chapter X. The Tribulations of The Mason Bee | 1972 |
| Chapter III. Another Prober (Perforator) | 1696 |
| Chapter XVI. A Parasite of The Maggot | 1903 |
