168 THK CANADIAN' ENTOMOLOGIST. 



A FEW OBSERVATIONS ON THE APPLE MAGGOT 

 PARASITE— BIOSTERES RHAGOLETIS, 

 RICHMOND. 



RY r. A GOOD, TKUKO, NOVA SfOTlA. 



In the September number (1015) of the Ctmadian Ento- 

 mologist appeared an article wriiun 1)\ Mr. W. ('. Woods of Orono, 

 Maine, in which he discussed the presence of the new ajiplc maggot 

 parasite, Biostercs rhagoJetis. As he had not seen the insect at 

 work, the following short account should l)e interesting since it 

 throws some light upon the manner in which the maggots are 

 parasitized. 



In August of this \ear, while obscr\ing the o\iposilion liabits 

 of tlu> apple maggot near Digliv, Nova- Scotia; my attention was 

 drawn to se\cral small, brownish insects which were fl\'ing al)Out 

 the leaves. PresentK' one of tlu-m alighted upon an apple, and 

 after slowly crawling o\er it in an erratic fashion for a few minutes, 

 it raised itself high on its legs and began prodding the skin of the 

 apple with its o\ipositor. Pre\ioush' this instrument had been 

 stretched out l)ehind the abdomen in a hori;contal ])osition. but it 

 was now bent under it, and down in ;^ vertical manner. I'irst 

 using the two hea\ier and outer pairs of the ovipositor to pierce 

 the skin, the\- were eventually raised up slightl>' while the lighter- 

 coloured, more slender egg-tube was plunged into the apple to a 

 depth of about one-cjuarter of an inch. After a pause of a few 

 seconds the whole was withdrawn and the insect moved to a new 

 spot, recommencing the operation at once. Five punctures were 

 made in rapid succession before I caught it. This insect was later 

 determined by Mr. E. A. Richmond, of Cornell University, as 

 Biosteres rhagoletis. 



Thus-it appears ..hat this parasite is a larval one, and this, no 

 doubt, accounts for the high percentage of mortality among the 

 larvse and pupae of the apple maggot. 



May, 1916 



