PROCEEDINGS, 1915. 67 



The length of life within the apple depends upon factors such as the 

 weather, and the state of maturity of the apple. Development is natur- 

 ally hastened in warm weather and retarded in cold. The growth of the 

 maggot is, also, very closely correlated to the maturing of the apple, as 

 with the increase in sugar in the apple, as it ripens, the maggots naturally 

 develop more quickly. Hence if eggs are deposited in already ripening 

 fruit, the resulting maggots would rt ach maturity sooner than if the apple 

 had been less mature. Thus it is almost impossible to give any definite 

 length of time, although approximately it can be placed at four weeks. 



When the maggot has reached full growth, it works its way out of 

 the apple and into the ground to a depth of from one to two inches deep 

 in sandy loams, and less so, in those of a clayey nature, depending upon 

 the porosity of the soil. There is also a great mortality among the lar- 

 vae, but through stress of inspection and counting, we were unable to car- 

 ry on experiments to determine what it is. Probably a great deal of this 

 is due to the parasitism of Biosteres rhagoletis. 



Pupa. 



The pupa is small, cylindrical and of the size of a grain of wheat, and 

 very much of the same color. The size varies with the sex of the flies. 

 Thus those to produce males are small, while those which produce fe- 

 males are larger. This difference in size was noted last spring when we 

 were counting our pupae, and so, 47 of the small ones were set aside and 

 48 of the large ones. By the end of the season, five males and one female 

 had emerged from the former lot,and five females from the latter,showing 

 that the size of the pupae depends upon the sex of the forthcoming flies. 



There is a great mortality amongst the pupae. In our check cages, 

 in which were untreated pupae, we only had an emergence of from 5 to 

 25 per cent. A great deal of this is the work of the parasite, as it has been 

 proved that the adult parasite emerge from the pupal cases of their vic- 

 tims. Weather conditions account for much of it also, as drying has a 

 very injurious effect upon the pupae. 



Control. 



1. Destruction of Fallen Fruit. Infested fruit falls to the ground pre- 

 maturely, and the maggots stay within the apples for from two to four- 

 teen days before they emerge. Hence if these drops are gathered and 

 destroyed in some way, the maggots within would also be destroyed. 

 These apples could be fed to hogs, taken to the cider mills or evaporators 

 1 uried in deep pits, but covered first with quicklime. Calves and hogs 

 e orchard are very good to keep the windfalls picked up, but even 

 they will leave a good many from which maggots will emerge, to result 

 the following spring in new flies and further infestation. 



