THAT INFEST THE VINE. 



171 



The Acari frequently attack the leaves of the 

 Vine early in the summer ; and as their increase 

 in dry weather is amazingly quick and great, they 

 will, without some method of controul, soon 

 greatly endamage, and, in time, totally destroy 

 the foliage. 



They generally reside and breed on the under- 

 side of the leaves, and the infested leaves are 

 very distinguishable as soon as they are attacked 

 by them ; for the insect wounds the fine capillary 

 vessels with its proboscis, and this causes the 

 upper surface of the leaf to appear full of very 

 small dots, or spots of a light colour. When the 

 Acari are very numerous, they work a fine web 

 over the whole under-side of the leaf, as also round 

 the edges thereof ; and it is curious enough to 

 observe, that they commonly carry this web in a 

 straight line, from one angular point of the leaf 

 to another, on which boundary line, in a warm 

 day, they pass and repass in very great numbers. 



The Acari, however, do not confine themselves 

 to the leaves only, but attack the bunches of 

 grapes also, especially at the time when they are 

 almost ripe ; and as they extract the juices from 

 them, the grapes soon become soft, flabby, and 

 ill-flavoured. 



2. The Thrips. This species abounds in most 

 hot-houses, and is hurtful to most plants kept in 

 them. It is often injurious to Vines growing 

 there ; and, as I have observed, more particularly 

 so to the sorts that produce white berries. 



