PRIMROSE. 5'J 



minuteness often destroys a whole plantation before 

 the cause is ascertained. This is the little red 

 spider Acarus, which forms its web on the under 

 side of the leaves, where it multiplies with such 

 rapidity as soon to devour and poison the whole 

 plant, although the insect itself is scarcely visible 

 without a magnifying glass. The first effect of its 

 attack is observed by the leaves becoming yellow 

 and spotted. When this is observed, the plants af- 

 fected should be taken up, and soaked for two or 

 three hours in a strong infusion of tobacco-water, 

 and then replanted in a fresh soil, or compost, but 

 by no means in the same situation, as there would 

 be danger of there being many of these little spiders 

 left on the ground, which would immediately return 

 to the plants. Maddock observes that u the red 

 spider seldom attacks such plants as are in a state 

 of vigour, or when the weather is cold and wet ', it 

 generally commences its depredations in the early 

 part of summer, and continues them as long as the 

 heat and dryness of the weather favour its existence: 

 the juices also of the plants being then more viscous 

 and saccharine, afford it more suitable nourishment 

 than at any other season." 



