260 CULTURE OF THE GRAPE. 



RED SPIDER (Acanis tellarius). 



This minute insect delights in a dry atmosphere, and is 

 destroyed by continued humidity : consequently we sel- 

 dom find it troublesome in the open air, except in very 

 dry seasons. It almost invariably makes its appearance 

 in the greenhouse or grapery that has been kept hot and 

 dry; and soon disappears when these conditions fail. In 

 dry seasons, we sometimes see the effect of the insect in 

 small, light spots, and the generally sickly, dry, and yellow 

 color of the leaves. The insect is so minute as to be 

 scarcely discernible to the naked eye; but attaching itself 

 generally to the under surface, as the softer part of the 

 leaf, it spins a fine film as a protection, and subsists by 

 suction upon the leaf. When in sufficient quantity, it is 

 as exhausting to the plant as the thrip. But there is no 

 excuse for this ever happening. In addition to humidity, 

 sulphur is a sovereign remedy. In the grapery, it may be 

 sprinkled upon the flues, or dusted upon the foliage ; and, 

 in the open air, it should be used precisely as directed for 

 mildew. 



