56 



THE REPORT OF THE 



No. 33 



RHAGOLETIS POMONELLA AND TWO ALLIED SPECIES 



(Trypaneidce, Diptera) 

 C. Howard Curran, Ottawa 



In volume fifty-one of the Canadian Entomologist (1919), Mr. W. 

 Downes, of the Entomological Branch, gave a complete historical account of 

 the occurrence of a species of Trypaneidee, supposedly Rhagoletis pomonella, in 

 British Columbia and mentioned also five specimens from California which had 

 been described as R. zephyria by Snow. In view of the excellent published 

 account by Mr. Downes, it is unnecessary to again cover this field fully, but it 

 seems advisable to mention the main points and add such information as I 

 have received from Mr. Treherne, who first discovered this insect at Penticton, 

 B.C., in 1916. 



In the first place both Dr. Doane and Dr. Aldrich have considered the two 

 species found on the Pacific coast identical with R. pomonella, the true apple 

 maggot. I have a type specimen of R. zephyria Snow before me, very kindly 

 loaned for study by Prof. S. J. Hunter, of the University of Kansas. It is 



evidently quite distinct from the other species as is hereinafter shown. The 

 species found in British Columbia is readily separated from pomonella and in 

 addition to slight external characters I find tangible differences in the genitalia 

 of the male. 



The outstanding fact concerning R. symphoricarpi, the species found in 

 British Columbia, is its striking monophyllic habit. According to Downes 

 and Treherne it never attacks apple and is found in the larval stage only in the 

 fruit of the snowberry (Symphoricarpus racemosus Michx.). Extensive search 

 was conducted to determine whether the insect attacked apples, haws or other 

 fruits such as often serve as hosts for the apple maggot, but no trace of the 

 maggots was found in anything but the snowberry. 



Mr. Downes suggested that P. symphoricarpi represented a biological race, 

 but it is quite evident that the species is distinct. Dr. Aldrich stated that he 

 could see no tangible difference between the western and eastern specimens, but 

 I believe they may readily be separated in almost all cases, and the males 

 assuredly can be by dissection of the hypopygium. There are, in many species, 



