244 DIPTERA OE TRUE FLIES. 



the summer the fly comes forth in about two weeks. There are 

 many generations in the year : the last all turn to puparia, and 

 remain as such in the soil and in the decaying leaves all the 

 winter. The attack is sometimes very serious, especially when 

 the ova are laid on very young plants after they have got into 

 rough leaf. If the brood comes when only the cotyledons 

 show, then the maggots die, as the seed-leaves shrivel up. 

 Sugar Beet is also attacked. 



Prevention and Remedies. — There are three points worth 

 mentioning : first, the destruction of winter puparia by the 

 usual methods of deep ploughing ; secondly, the application 

 of some stimulating manures to the attacked crop, especially 

 nitrate of soda ; and thirdly, spraying, where a " strawsoniser " 

 can be used, with paraffin emulsion. There being many gen- 

 erations, we should try and kill the first. 



Family CHLOROPIDJE. 



The Gout Fly (Chlorops t.exiopus). 



In poor land barley may often be seen stunted and swollen, 

 and unable to burst its way out of the ear. This peculiar 

 appearance is called " Gout," and frequently causes a serious 

 deficit in the crop. This swollen diseased state of the plant is 

 produced by a small fly belonging to the Chloroju'dw, called the 

 Ribbon-footed Corn Fly or Gout Fly (Chlowpf: iceniopus). It 

 is a small fly about one-eighth of an inch long, thickly built ; 

 the thorax is yellow, and has three dark blackish-green stripes 

 on it ; the abdomen is greenish-brown with dark bands across. 

 The female lays her eggs separately, one larva sufticing to pro- 

 duce this gouty appearance. She deposits them on the barley 

 plant just when the ear is still in the sheathing leaves, either 

 within the leaves or so that the young larvae can speedily enter. 

 The larvse first devour some of the developing grain on one side, 

 and then commence to tunnel down the stem to the first node. 



