DIPTEEA OR TRUE FLIES. 223 



June. Generally speaking, the Frit Fly damage can be re- 

 paired if taken in time. Barley is attacked on the Continent 

 as well as oats, but in Britain only the latter suffers. "We can 

 early detect its presence by the central leaves here and there 

 turning brown or yellow, and on examination a small maggot 

 will be found in the shoot. The Frit Fly is a small, black, 

 shiny dipteron about one-eighth of an inch in length. The eggs 

 are laid by the females of the first brood upon the young oats, 

 and the maggots coming from these live in the heart of the 

 young plant. The larvte are cylindrical white grubs, one-eighth 

 of an inch long when mature, and have a pair of branched 

 spiracles projecting on each side near the head, and two 

 other tuberculate spiracles on the tail. They pupate in 

 the outer dying leaves, as small reddish-brown bodies, from 

 which the flies come from the end of June to the end of July. 

 The second brood after hatching out sometimes attacks the 

 corn, laying its eggs in the ear. One instance of this attack in 

 barley has come to my notice. The later hatched ones live as 

 larvae in wild grasses, and having matured are ready to attack 

 the oats in the spring. 



Prevention and Remedies. — In some cases where the whole 

 crop is badly attacked it is advisable to plough it up. Should 

 this be done, it is important to plough in as deeply as possible, 

 so as to effectually bury the insects, which speedily hatch out. 

 If on the first signs of attack we use stimulating manures, we 

 can still get a good crop, the healthy plants tillering out over 

 the space left by the dying ones. 



The Caueot Fly (Psila EosiE). 



Every one who takes an interest in the garden knows the 

 disease called " rust " in carrots. Eust is duo to the larvae of 

 one of the flies belonging to the family Psilidre. The Carrot 

 Fly {Psila rnsie) (fig. 113, 7 and 8) is a small fly less than half 

 an inch in expanse of wing, of a shiny metallic green colour. 



