ILLUSTRATIONS. 



PLATES. 



Page. 



Plate I. Figs. 1-3. — Method of covering small tree with bell or hoop tent 14 



II. Figs. 1-3. — Method of covering small tree with sheet tent by means of 



poles 20 



III. Figs. 1-5. — Successive stages in the operation of shifting a sheet tent 



from one tree to the next in the row. Fig. 6. — First tent ready for 

 introduction of chemicals; "tent men" shifting the second tent 

 in the series 20 



IV. Fig. 1. — Commissary tray: Open compartment (tin lined) for cyanid 



at right, balances and torch in the middle, compartment for acid 

 pitchers and glass graduate at left. Fig. 2. — Top of derrick, show- 

 ing method of attaching pulley and guy rope. Fig. 3. — Base of 



derrick, showing method of constructing braces 22 



V. Fig. 1. — Raising 33-foot derricks to an upright position. Fig. 2. — Der- 

 ricks in position (one on each side of tree), supported by guy ropes; 



pulleys hooked to catch-rings in the tent 28 



VI. Fig. 1. — Front edge of sheet tent raised to tops of derricks, ready to be 

 pulled over tree. Fig. 2. — Sheet tent ready for introduction of 



chemicals 28 



VII. Fig. 1. — Eighty-foot tent covering large seedling orange tree, showing 

 tent graduated for the purpose of enabling operators to use dosage 

 table given in the appendix. Fig. 2. — Carrying 5-gallon crocks con- 

 taining acid and water under the tent, preparatory to introducing 

 the cyanid 32 



TEXT FIGURES. 



Fig. 1. Plan for construction of octagonal sheet tent 50 feet across, showing lines 



used in constructing octagon 16 



2. Method of attaching hooks to tent when covering trees with aid of der- 



ricks 18 



3. Plan for schedule board, showing convenient arrangement 22 



4. Diagram of regularly set grove in process of fumigation with an outfit of 



four tents 23 



5. Diagram of grove with alternating trees; first four rows in process of 



fumigation with four tents; three sets of trees fumigated, the tents 

 being moved from south to north 24 



6. Diagram showing method of marking tents to aid in oljtaining dimen- 



sions of inclosed space when covering tree 32 



7. Tent marked to aid in estimating dosage, in position for fumigation 33 



8. White fly (Aleyrodes citri) : Stages and details 59 



9. White fly {Aleyrodes citri): Adult male and female and details 59 



10. Florida red scale ( Chrysoviphalits fims) : Stages 61 



11. Purple scale {Lepidosaphes heckii) : Stages 62 



6 



