DESTRUCTIVE INSECTS. 301 



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especially of new budded or grafted plants, causing- a 

 serious loss to the nurseryman. Being a hardy insect, 

 they cannot be assailed by any nauseous dilution or 

 powder applied to the soil ; but probably something 

 of the kind thrown on the stems and heads by a 

 syringe might protect the buds. 



Red Acarus or Tick. This is commonly called 

 the red spider. They are a minute apterous insect, 

 though a great plague to the forcing gardener. It 

 infests the leaves of vines, peach-trees, and almost all 

 other plants in the stove or hot-house ; puncturing 

 the cuticle of the leaves and young shoots to extract 

 the sap, and causing its escape, so that the parts lose 

 their vitality and die. This insect is called a spider? 

 because it spins or ejects a web, not for the purpose 

 of entangling flies like the true spiders (Aranea), but 

 for forming a kind of defence against humidity which 

 is most annoying to them. Indeed a moist atmo- 

 sphere, and water frequently and forcibly applied, is a 

 good remedy to banish and prevent their increase. 

 But sometimes they become so numerous in collections 

 of plants to which excessive watering would be preju- 

 dicial, that it is necessary to extirpate them by suffo- 

 cation, which is done by the vapour of flour of 

 brimstone smeared on the hot flues of the house, or 

 from a chafing dish made for the purpose. It has also 

 been found that copious moisture with a very high 

 temperature will expel these insects. There are 

 several other plant ticks, that are comparatively 

 harmless. One sort lives on the leaves of grass, causing 



