76 



CORN AND GRASS. 



yearly as one of our regular Barley pests, and sometimes (as 

 in 1887) to a seriously injurious extent. 



^grmTEp. czuiisiJ^ 



CMoroiJS fccniopus : 2 — 6, 11, maggot, chrysalis, and fly, nat. size and mag- 

 nilied ; 7 and 8, Cudiniiis n'ujcr ; 9 and 10, Ptcrumalus micans (parasite flies), 

 nat. size and magnified ; 1 and 12, furrowed Corn-stem. 



The attack takes its common name of " Gout " from the 

 swollen state of the heads when the ear is unable to burst the 

 sheaths. Whilst the plant is still young, and the forming ear 

 is wrapped in the sheathing leaves, the fly places her eggs 

 either within these leaves, or so that the maggot can make its 

 way through them to the ear ; there it usually eats away 

 some parts of the lower portion of the ear, and then gnaws, 

 or rather tears, a channel down one side of the stem to the 

 uppermost knot, and beneath the leaves the maggot changes 

 to a reddish chrysalis, from which the Gout Fly appears 

 about harvest-time. 



The injured furrow down one side of the uppermost joint is 

 the characteristic of the attack — joined to the enclosure 

 of the ear in the sheathing leaves. This may be to any 

 degree, from the plant itself being so stunted in early growth 

 that the ear hardly forms, and the plant altogether looks like 

 a thin side- shoot of Indian-corn, up to the ear freeing itself 

 entirely, but still suffering from the stem being maggot-eaten 

 (see figs. pp. 77 and 78). The maggot is yellowish- white and 

 legless, tapering to the foremost end which contains the 

 mouth-hooks, and blunt at the tail (see fig.), and the ochre- 

 coloured or reddish chrysalis case may often be found in the 

 blackened furrow caused by the gnawing of the maggot. 



