Remedial Measures and Insecticides. xxiii 



III. Simplicity. — All the parts of the pump should be readily- 

 accessible and removable, so that, should anything go wrong, they 

 may be taken to pieces and cleaned, or damaged parts renewed. 

 The want of these facilities is a serious fault in many machines, 

 the slightest injury necessitating the sending of the whole apparatus 

 to the repairers. 



IV. The Production of a Uniform and Effective Spray. — 

 The continuity and force of the flow is dependent upon an 

 air chamber in the pump, this feature constituting a ' force- 

 pump.' On this account all hand syringes are almost useless. 

 The nature of the spray is regulated by the form of nozzle 

 employed. The chief object is to break up the liquid into such a 

 fine spray that it will penetrate the thickest foliage in the form of 

 a dense mist and come in contact with every part. For this 

 purpose one of the * cyclone nozzles ' is most admirably adapted. 

 But where it is necessary to throw the liquid to a considerable 

 distance, as, in spraying large trees, a nozzle throwing a coarser 

 spray must be used. It is advisable to have several interchange- 

 able nozzles to suit the different kinds of work. There should 

 always be a detachable cap to the nozzle, so that any obstruction 

 may be quickly and easily removed. Many nozzles are provided 

 with a fine point, held back by a spring, but which, when pushed 

 forward, clears the aperture. 



A few further remarks may be quoted from Mr. Lounsbury's 

 report, in which he gives some recommendations for the care of 

 spray pumps. ' Before a spray pump of any kind is put away 

 after use, it should be thoroughly washed and clear water pumped 

 through it ; hot water answers much better than cold if sticky or 

 soapy washes have been used. The working parts should be 

 occasionally oiled, and if the paint on the iron parts becomes worn 

 away it should be renewed. Attention to these details will preserve 

 the pump for a long period, while, if they are neglected, the pump 

 may never save its initial cost' 



Before quitting the subject of general remedial measures and 

 entering upon detailed descriptions of particular processes, some- 

 thing should be said upon the important question of the 

 introduction of ' natural enemies ' of the Coccidce. The same 

 circumstances that make an imported pest so exceptionally 

 dangerous act in our favour in the importation of beneficial 

 insects. Just as the absence of its established natural enemies 

 enables an insect pest to multiply without hindrance, so the 



