90 THE NEW ONION CULTURE 



scarce, and by July 15, none were to be found. Begin- 

 ning with July, considerable rain had fallen, which 

 may have hastened their disappearance. 



"This species is injurious to the foliage of plants. 

 On the onions, it chafes off the epidermis from the 



Fig 52 PLANT ATTACKED BY THRIPS 



green leaves, thereby causing them to dry out, whiten 

 and frequently die. On the cabbage and cauliflower 

 their effects are about the same. They are much more 

 abundant on the lower surface of the leaves, where 

 they chafe off the leaf substance, much as in their 

 attack on onions. 



"According to Mr Th. Pergande, assistant ento- 

 mologist, United States department of agriculture, the 



