﻿THE MEXICAN ORANGE MAGGOT 329 



lo deposit its eggs. These eggs hatch within the body of the maggot, and 

 the latter, consequently, never come to maturity, but die before pupation 

 occurs. This parasite has heretofore been known as Cratospila nidibnnda. 

 Many specimens were taken by the writer in the very act of stinging the 

 fruit, oranges, mangoes and guavas, and depositing eggs in the maggots. A 

 determination on these parasites by Mr. Viereck of the U. S. Department 

 of Agriculture places them in the genus Diachasma ; he is unable to assign 

 to it a specific name. The monograph of Bracontdac by Szepligeti has no 

 mention whatever of the name Cratospila ritdibunda. The name heretofore 

 known is possibly a manuscript name only and should in that case be dropped 

 trom use. 



In dealing with a trouble which is very wide-spread, and in a tropical 

 country where fruit trees attacked by it grow easily with little care and 

 often in a wild state, and where for many reasons an artificial remedy is 

 very hard to apply, one is very apt to favor natural control by parasites. Let 

 us consider again the previously proposed measures as compared with new 

 measures wherein parasitism figures mostly. Mr. Isaac in his report stated 

 that the work of the parasite was not, as yet, very effective, since only from 

 ten to fifteen percent of the larvae were parasitised, but it was hoped that the 

 percentage would increase materially in the future. Since it was impossible 

 to stay in one place long enough to study the life-history or determine the 

 percentage of parasitized larvse, no definite statement can be made as to 

 whether or not it has increased. Now if the trouble is to be removed b\' 

 destroying al! the maggots in <;// infested localities for a period long enough 

 to eradicate the fly entirely, well and good. But if one spot is overlooked 

 or if a few flies continue to exist, then the whole fight will have to be re- 

 peated. On the very face of it, it is easy to see that a complete stamping out 

 of the pest by the above mentioned methods is utterly impossible, for reasons 

 already given, whereas to increase artificially the number of the Diachasma 

 parasites will undoubtedly reduce the trouble to a minimum and hold it there. 



Now, as was said above, great hopes have been entertained that the 

 parasite would increase to larger numbers, but, while entertaining these hopes, 

 the government have simply been destroying the objects of their hope by burning 

 or burying the parasitized maggots — except when this was not enforced. .\nd 

 when no fruit was being destroyed the fly and the parasite maintained their 

 former ratio of equilibrium. This is undoubtedly the present condition of 

 affairs. If, then, the methods formerly used have not proved entirely satis- 

 factory and, further, have prevented the increase of parasites, and since 

 parasitism is the most logical and effective method of controlling the pest, then 

 some means should be devised whereby a rapid and large increase of the 

 Diachasma parasites can be effected. 



A very simple, economical and wholly practicable means may be found 

 in the following suggestion : In a word, confine the parasitized maggots in such 

 a way that the parasite can escape when it emerges while the fly mu.st remain 

 and die in confinement. This is very simple indeed and easily performed, 



