enemy to apples. The flies do not spread rapidly, and hence individ- 

 ual orchards or certain varieties of apples may suffer severely, while 

 those adjoining may be little injured. Although the pest was bred 

 from haws, in 18G7, in Illinois, there has been but one record of its 

 infesting apples in that State." 



FOOD PLANTS. 



The natural food of the apple maggot is wild haw (Cratsegus), 

 and probably several species are infested. It was bred from haws 

 by Walsh in Illinois, by Cook in Illinois and Wisconsin, and by 

 Comstock at Washington, D. C. Despite its supposed general occur- 

 rence in the fruit of this plant, no further records of breeding from 

 haws have been found, and Professor Harvey states that it was not 

 found in haws in Maine. During the past three years the Bureau of 

 Entomology has collected or received fruit of Crataegus spp. from 

 various parts of the country, but has not observed it to be infested 

 Avith the apple maggot in any instance, and it appears quite doubtful 

 if the (distribution of the species is as general as is that of its native 

 food plants. 



The early statements of the probable feeding of this species on crab- 

 apple appear not to have been based on actual observations, and 

 aside from Rilej^'s record of its occurrence on crabs,^' no definite data 

 have been presented to show that it infests this fruit. Professor 

 Harvey thought it improbable that this fruit would be used, for the 

 reason that it is quite green and hard during the period of flight and 

 oviposition of the flies. The insect was found infesting plums and 

 late cherries in northern Michigan, b}^ Professor Cook,^ in 1889, 

 though no additional records of its occurrence in these fruits have 

 been seen. 



Of apjDles, sweet and subacid summer varieties are worst attacked, 

 but fall and winter sorts are also infested, including distincth' acid 

 varieties. Professor Harvey has prepared a list of apples showing 

 their relative degree of infestation as observed by him in Maine 

 during his careful study of the apple maggot.'' 



"Cordley, Orchard and Garden, 1889, p. 192. 

 ''Am. Agric. 1872, p. 203. 



^ Second Ann. Rept. Mich. Agric. Exp. Sta., i). 153. 

 ^ Loc. cit. 

 [Clr. 101] 



