DISEASES AND INSECTS ATTACKING THE ROSE. 143 



color, and rathor larger than a j^ea, may often be seen on 

 rose-bushes. Each of thciu contains a single grub, and 

 this in due time turns to a gall-fly. Its head and thorax 

 are black, and rough with numerous little pits ; its hind- 

 body is polished, and, with the legs, of a brownish-red 

 color. It is a large insect compared with the size of its 

 gall, measuring nearly one-fifth of an inch in length, while 

 the diameter of its gall, not including the prickles, rarely 

 exceeds three-tenths of an inch." 



Cynips dlchlocerus, " or the gall-fly with two-colored 

 antennae, is of a brownish-red or cinnamon color, with four 

 little longitudinal grooves on the top of the thorax, the 

 lower part of the antennne red, and the remainder black. 

 It varies in being darker sometimes, and measures from 

 one-eighth to three-sixteenths of an inch in length. Great 

 numbers of these gall-flies are bred in the irregular woody 

 galls, or long excrescences, of the stems of rose-bushes." 



Cynips semiplceus. — "The small roots of rose-bushes, 

 and of other plants of the same family, sometimes pro- 

 duce rounded, warty, and woody knobs, inhabited by 

 numerous gall-insects, which, in coming out, pierce them 

 with small holes on all sides. The winged insects closely 

 resemble the dark varieties of the preceding species in 

 color, and in the little furrows on the thorax ; but their 

 legs are rather paler, and they do not measure more than 

 one-tenth of an inch in length." 



Rose-Slu^^, Selandrla Hosce, of Harris, who gives the 

 following account: "The saw-fly of the rose, which, as it 

 does not seem to have been described before, may be call- 

 ed Selandrla Jiosre, from its fxvorite plant, so nearly re- 

 sembles the slug-worm saw-fly as not to be distinguished 

 therefrom except by a practiced observer. It is also very 

 much like Selandrla harda, Vltls, and jyyymcea, but has 

 not the red thorax of these three closely allied species. 

 It is of a deep and shining black color. The first two 



