ILLUSTRATIONS, 



Page. 

 Fig. 1. Map showing principal localities in southern California where citrus 



fruits are produced 10 



2. Leaves and branch of orange infested with purple scale (Lepidosaphes 



beckii) 11 



3. Fruit of orange infested with purple scale 12 



4. Branches of orange infested with black scale (Saissetia olex) 12 



5. Leaves and branch of orange infested with red scale (Chrysomphalus 



aurantii) 13 



6. Orange tree almost destroyed by red scale 14 



7. Orange tree showing branches at center partly destroyed and stripped 



of leaves by purple scale 15 



8. Tray commonly used for carrying the chemicals of fumigation from 



tree to tree 18 



9. Man carrying tray and water bucket 19 



10. A typical California lemon orchard with row of fumigation generators 



placed ready for use the following night 20 



11. Outline of a fumigation tent marked according to the Morrill system. . 28 



12. A fumigation tent marked after the Morrill system 29 



13. Chart showing total amount of gas evolved when different propor- 



tions of water are used 38 



14. Orange blossoms at an early stage of development 50 



15. Lead-lined tank used in San Bernardino County for removing sul- 



phuric acid from drums and for filling jugs 53 



16. An improved pipe for removing acid from drums 54 



17. Sii^honing acid from a drum by means of a rubber hose 54 



18. Carboy resting against a heap of dirt to facilitate pouring the acid. ... 55 



19. Carboy with handles attached to facilitate pouring the acid and carry- 



ing the carboy 56 



20. Zinc-covered top for protecting cyanid in the field 57 



21. A cover device attached to a fumigation generator 58 



22. Difference in the direction taken by gas escaping from an open gen- 



erator and from one covered with the corrugated lid 59 



23. Cart used with the improved system of fumigation 60 



24. Earthenware acid jar with attachments for field use 61 



25. A table which can be used instead of a cart in fumigation over very 



rough ground 62 



26. A row of tented trees, and cart at one end ready for dosing 62 



27. Dosing a tree 63 



28. Dosage schedule No. 1 65 



7 



