330 POMONA COLLEGE JOURNAL OF ENTOMOLOGY 



but, as far as I have been able to ascertain, it has never been suggested, 

 much less tried. 



The simplest method of carrying this out is by means of a small shed 

 built irom the cheapest and handiest materials ; in most places this would be 

 adobie. It should be large enough to hold quite a large quantity of fruit 

 without piling it up any more than is necessary, so that infested fruit could be 

 thrown in and the larvae allowed to mature and pupate within the shed. The 

 shed should be absolutely without a hole or crack large enough for the adult 

 fly to escape through. A part of one end is covered with wire screen, instead 

 of adobe. The meshes of this screen must be 3 millimeters (one-eighth of an 

 nich), which is just large enough to allow the parasite to escape but not the 

 fly, as was shown by experiment. On each side of the shed, at a height of 

 about three feet from the ground, are several openings large enough to dump 

 the fruit through; by inserting a short flume into the openings, beveled at 

 the end within the shed, and by hanging a bottomless canvas bag over the 

 beveled end of the flume, a trap entrance could easily be made, so that fruit 

 could be dumped in with no fear of the insects within escaping. 



Since the increase of parasites would be in direct proportion to the amount 

 of fruit enclosed in the sheds, as large a percentage as possible of the fruit 

 .which has fallen to the ground should be so disposed of. Of course each 

 shed would hold only a certain amount successfully, but additions could be 

 made to the fruit at intervals of about two weeks or more, depending on 

 the time required for pupation. If there is a surplus of fallen fruit which 

 can not be so disposed of, it should be gathered and burned wherever possible 

 or feasible, thus diminishing the number of flies, at least. 



A thorough trial of this in many of the localities should, without a doubt, 

 increase the parasites sufficiently so that within three years, or possibly four, 

 the pest would be reduced below the danger line. Alinor accompanying 

 remedies might assist enough to blot out the trouble entirely. 



A carbolic emulsion should prove very effective as a spray to be used 

 on the adult flies, which, with very few exceptions, stay on the fruit or leaves. 

 This spray is effective enough to kill the flies which it touches, and in addi- 

 tion to this it leaves on the trees such an odor that the surviving flies would 

 be kept off for some time. A third function of the same spray is the dripping 

 down of the liquid onto the ground under the trees and undoubtedly killing 

 many of the pupas and transforming larvae which may have escaped between 

 the daily clean-up of the fallen fruit. A secondary but no less beneficial 

 result from the application of the spray is the cleaning up of the trees and 

 fruit, ridding them from any scale insects and accompanying smut. These 

 latter are, of course, mere suggestions, but well worth a good trial. The 

 formula for a good spray of carbolic emulsion is as follows : 



Carbolic acid (crude) 5 gallons 



Whale oil soap 40 pounds 



Water 40 gallons 



This stock solution should be diluted one to twenty parts with water 

 before using it as a spray. 



