J 34 



THE BOOK OF GARDENING. 



be taken in hand directly it is observed, as it spreads very 

 rapidly, and is fatal to the rosarian's chances of success. 



Rose Galls. — The presence of these excrescences, often of 

 large size, upon Rose-trees both wild and cultivated, is usually 

 puzzling to the gardener. The most conspicuous is the Rose 

 Bedeguar (Fig. 65), a leaf-gall of large size, and conspicuous 

 by reason of the long red or green hairs. It is due to the 



Fig. 65. — Stages in the Life-History of the Bedeguar Gall. 



punctures of one of the Gall-flies (Rhodites rosce), a very 

 puzzling lot of extremely minute insects. These creatures 

 puncture the parts in the process of egg-laying, and the 

 movements of the larva, combined with the exudations, affect 

 the tissues of growing cells which are capable of further 

 division. This is the theory of the late Professor Riley, 

 who paid considerable attention to this most intricate but 

 interesting subject. In the illustration (Fig. 65), 1 is the Bedeguar 



