THE RED-NECKED CANE-BORER 



263 



small borer, which is very similar in appearance and which be- 

 longs to the same family as the flat-headed apple-tree borer. 

 This swelling, which is a pithy gall, has been named by Dr. 

 Riley the Raspberry Gouty -gall 

 Rubi podagra although there 

 seems to be no good reason for 

 applying a special name to the 

 gall so long as the insect which 

 produces it is equally well 

 known. The galls are usually 

 confined to the main canes, and 

 may be near the base, or two 

 or three feet above ground, 

 though sometimes even the 

 more vigorous laterals are at- 

 tacked. The injured canes may 

 put forth leaves and blossoms, 

 but the fruit seldom ripens, and 

 the cane dies before the end of 

 the season. 



The larvae burrow in a spiral 

 direction, confining themselves, 

 in the early stages of their ex- 

 istence, wholly to the sap wood, 

 and by this means girdle and 

 kill the cane. According to 

 one observer, this habit of 

 girdling the cane in order to 

 kill it the first season seems 

 to contribute to the safety of 

 the larvse, which otherwise 

 freeze and perish, perhaps owing to the greater quantity of sap 

 which surrounds them in living canes. They are said to be 

 more frequently destroyed in this manner in blackberries than 

 in raspberries. Like the crown-borer, it often escapes detec- 

 tion by reason of the belief that the injury is due to winter- 

 killing. 



Fig. 36. Agrilus 

 ruJicoUs. 



Fig. 37. Work of 

 red-necked Cane- 

 borer. 



