June, '08] JOURNAL OF ECONOMIC ENTOMOLOGY 171 



americana), but it has been found that it is another species (Ancts- 

 trepha serpentina) . 



Means of control. — For the last seven years the pest has been com- 

 bated, in Yautepec, by burning or burying the fallen fruit from the 

 trees and cleaning of the orchards ; the old wooden and thorny fences 

 are replaced by wire fences; the orchards are carefully cultivated 

 and the intercalar crops of sugar cane, "jicama," (Dolichos), etc., 

 have been suppressed. One of the means that have been tried during 

 these last months consists in injecting in the fallen fruits some gaso- 

 line or benzine, thus avoiding the transportation of heavy loads of 

 oranges to the incinerating furnaces or burying ditches. These in- 

 jections are performed by a workman who perforates the fallen 

 oranges not yet rotten with a nail or any pointed tool, in but one 

 place, so that the hole thus formed be of about the same diameter 

 as a large pencil ; then he squeezes the fruit in order to extract a large 

 amount of its juice, and another man gives him an ear-syringe filled 

 with gasoline or benzine, which is injected in a sufficient quantity, 

 that is, all that may be contained inside of each orange. 



The cost of this treatment is, approximately, from 15 to 20 dollars, 

 Mexican money, for every 10,000 fruits. I think that this amount 

 could easily be reduced if an automatic injector were used, which is 

 not necessary for the present. According to practical informations 

 from the agents of the commission, a workman may inject 250 oranges 

 an hour, and therefore six workmen at work for eight hours a day 

 will inject 12,000 oranges. The larva do not perish immediately, 

 but they fall into lethargy under the effects of the vapors from the 

 benzine, which slowly spread through the pulp of the orange and thus 

 impede the exit of the larvae already fully developed and ready to 

 bury themselves.^ 



Parasites. — Since 1907 I have tried, very earnestly, to find the para- 

 sites which might help in the destruction of the fly. At first was 

 discovered the Cratospila rudihunda, a species of wasp (Braconidae), 

 which lays its eggs on the larvae, through the skin of the guavas 

 and mangos, but unfortunately its ovipositor is very short and could 

 not penetrate to the interior of the oranges. This parasite could not 

 be bred and besides is very scarce in Yautepec. 



At Cuernavaca, a horticultural center of great importance, the 

 guavas and mangos are infested by the Trypeta ludens and acidusa, 

 but there are no orange groves in that place. With great care did I 



iMr. Froggatt says that in Australia they have been using petroleum with 

 water to attract the flies, but the experiments made at Yautepec so far have 

 given very little results. 



