| Chapter III. The Distribution of Sexes | 4431 |
| Chapter XII. The Halicti: a Parasite | 4884 |
| Chapter VIII. Parasites | 4865 |
| Chapter IX. The Theory of Parasitism | 5771 |
| Chapter X. The Tribulations of The Mason Bee | 6359 |
| Chapter III. Another Prober (Perforator) | 5503 |
| Chapter XVI. A Parasite of The Maggot | 5986 |
