27 



have been used with good results iu the work of the Gypsy Moth 

 Commission, both for street trees and iu the public parks. A steam 

 apparatus, however, of such a capacity that a pressure of 75 pounds 

 per square inch may be gained will enable the operation of four or 

 five lines of hose simultaneously. The rapidity of work will therefore 

 be doubled, and certainly by the use of two such pumps the shade trees 

 of any ordinary city can be gone over with sufficient rapidity to destroy 

 all insects within the required time. A boiler mounted on a truck, the 

 boiler to be complete with all fixtures, smokestack, bonnet, firing tools, 

 springs to the truck, and a pump having a capacity of 10 to 20 gallons 

 a minute connected with the boiler ready for operation, can be pur- 

 chased for a sum well within $500. This truck should be mounted on 

 wheels with broad tires, for running over sandy roads. Connecting 



FIG. 11. Fall webworm. Suspended larva and section of web natural size (original). 



this apparatus with a proper tank cart would be an additional expense, 

 not to exceed $100 for a tank of a capacity of 200 gallons. Such an 

 apparatus, furnished with hose and smoothbore nozzles of about one- 

 sixteenth inch iu diameter, when discharging under 40 pounds pres- 

 sure from each of several such nozzles, would spray about half a gal- 

 lon of insecticide mixture per nozzle per minute. 



A strong steam pump, to be used in connection with a small oil- 

 burning boiler, the whole apparatus on a smaller scale than that 

 described above, has been estimated at $275 by a prominent New York 

 firm, delivered on board the cars. 



There is no reason why an old steam fire engine could not be 

 readily arranged for this shade tree spraying work. In one or two 

 instances a steam fire engine has been used for this purpose without 



