MISCELLANEOUS GARDEN INSECTS 419 



mandibles being reduced to bristle-like structures. Their man- 

 ner of feeding does not seem to be clearly understood, though 

 Professor Quaintance states that the onion thrips frequently 

 rasps off and swallows pieces of leaf tissue. However, they are 

 able to destroy the surface tissue of the leaf so that it wilts, 

 and fields badly affected become blighted and white. 



This species has quite a list of food-plants, cabbage and cauli- 

 flower often being considerably injured. Among them may be 



FIG. 302. 1'he onion thrips (Thrips tabaci Lind.) very greatly enlarged. 

 (Photo by Quaintance.) 



mentioned turnip, kale, sweet clover, squash, cucumber, melon, 

 parsley, tomato, and several common garden flowers and weeds. 



Life History. The eggs are slightly less than Vioo of an inch 

 long too small to be visible to -the unaided eye elongate, and 

 curved somewhat kidney-shaped. They are laid singly just 

 beneath the surface of the leaf and hatch in about four days. 

 The young nymphs resemble the adults in shape, but are at 

 first almost transparent in color and then a greenish-yellow. 

 They are frequently found feeding in small groups. Both the 



