ATTACKING THE CANES. 305 



gall-fly. These soon change to pupae, and they in turn pro- 

 duce after a time the perfect insects, which eat their way 

 out through the substance of the gall, leaving small holes to 

 mark the place of exit. These galls are not only the abode 

 of the makers, the gall-flies, but are also frequented by other 

 species known as guest-flies, and the presence of these as well 

 as other parasitic species in company with the normal inmates 

 is apt to perplex the observer, and renders it more difficult to 

 discover the real authors of the mischief. This gall chiefly 

 affects the black raspberry; it also occurs on the blackberry, 

 and sometimes on the roots of the rose. 



Wherever these excrescences are found they should be col- 

 lected and burnt. 



ATTACKING THE CANES. 



No. 176. — The Raspberry Cane-borer. 



Oberea bimaculata Oliv. 



This insect in the larval state lives in the centre of the 

 cane, where it burrows a passage from above downwards, 

 often causing the death of the cane. Its natural home is 

 among the wild raspberries, but it has taken very kindly to 

 the cultivated sorts, and appears indeed to prefer them. 



The perfect insect is a long-horned beetle (see Fig. 315), 

 with a long and narrow black body, with the top of the 

 thorax and the fore part of the breast pale yel- 

 lowish; the wing-cases are covered with coarse Fig. 315. 

 indentations and slightly notched at the ends, and 

 there are two black spots on the thorax, which, 

 however, are sometimes wanting, and a third black 

 dot on the hinder edge, ju.st where the wing-covers 

 join the thorax. The beetles appear on the wing during tiie 

 month of June, and, after pairing, the iemale proceeds to 

 deposit her eggs, which she does in a very singular manner, 



20 



