INSECTS INJURIOUS TO RASPBERRY AND BLACKBERRY 469 



pithy swelling from one to three inches long and nearly an inch 

 in diameter, red or reddish-brown, with the surface divided by 

 deep longitudinal furrows into four or five ridges or parts. The 

 gall is caused by the larvae of a small black gall-fly, which is 

 about one-twelfth inch long, with red feet and antennee and four 

 transparent wings, almost lacking wing-veins. The insect passes 

 the winter in the larval stage in the galls, and if one be opened 

 at that season, there will be found about the middle a number of 

 cells about one-eighth inch long, each of which contains a single 

 larva. The larva " is about one-tenth inch long, white, with the 

 mouth-parts reddish, and the breathing pores and an oval spot 

 on each side behind the head of the same color." They change 

 to pup83 in spring and the flies appear a little later. Though 

 this gall is also very common on wild canes it rarely does 

 much injury. 



Control. The affected canes should be cut and burned during 

 the winter. 



The Raspberry-cane Maggot * 



The tips of young raspberry shoots sometimes droop and wilt 

 in the spring in much the same manner as when affected by the 

 cane-borer later in the season, and though blackberry shoots are 

 similarly affected they usually recover, but bear small gall-like 

 swellings like those shown in Fig. 339. This is the work of a small 

 white maggot, nearly related to and looking much the same as the 

 cabbage-maggot (p. 347), which girdles the inner bark of the 

 stem. Injury has been observed in New York, Canada, Michigan, 

 Pennsylvania, and recently it has become a serious pest in Wash- 

 ington, so that it is undoubtedly much more widely distributed 

 than the records indicate. The parent fly, shown in Fig. 338, 

 is grayish black, much resembling the house-fly, but slightly 

 smaller. 



Life History. The flies appear in April and deposit their eggs 

 as soon as the shoots are well above ground, continuing until early 



* Phorbia rubivora Coquillet. Family Anthomyidce . See Slingerland, 

 Bulletin 126, Cornell Univ. Agr. Exp. Sta., p. 54; W. H. Lawrence, Bulletin 

 62, Wash. Agr Exp. Sta. 



