388 



ON THE CULTURE 



along the veins of the leaves of plants, from which 

 it skips with great agility on being touched. 



The Thrips is a great enemy to the Vine while 

 he leaves are young and tender, especially to the 

 delicate sorts, whether they grow in the open air 

 or under glass ; but in the latter case they are 

 generally attacked with the greater severity. 



It is no uncommon thing to see in a hot-house 

 whole crops of French beans entirely destroyed by 

 them, especially late in the spring, when the weather 

 becomes warm. The Cape Jasmine, as well as 

 many other exotic plants, often fall a prey to these 

 minute insects. 



The Thrips may be destroyed by the same 

 methods as the Aphides. 



The Oniscus d , or Wood-Louse. As the Onisci 

 are exceedingly numerous in most hot-houses, I 

 shall on that account just mention them here, 

 although I have never known them to injure plants 

 except when first they rise from seed : this, how- 



d The Oniscus is of the Order Aptera. 

 Its Characters are : 

 The antenna? are setaceous, and bent. 

 The mouth is furnished with two palpi. 

 The head is intimately joined to the thorax. 

 The body is of an oval form, and composed of several crus- 

 taceous plates. 



The Oniscus ha3 fourteen feet. 



The Onisci change their skin like many other apterous 

 insects. 



They are very common in houses, gardens, and woods, and 

 are generally called Wood-lice. 



