320 A BOOK OF INSECTS 



prove very injurious to cereals. On Plate XLV is repro- 

 duced a photograph of five wheat ears gathered by the 

 writer from one crop in the month of July. The first is a 

 normal ear of average fruitfulness. The second is from a 

 plant attacked by the ribbon-footed corn-fly (Chlorops tceiii- 

 opus). This insect belongs to a family of little flies allied 

 to the Anthomyidce, one of its near relatives being the 

 infamous frit fly (Oscinis frit), which often works havoc in 

 oat fields. The female Chlorops lays her egg upon the 

 leaves which serve as a sheath for the forming ear. When 

 the larva hatches, it bores through these leaves, and takes 

 up a position at the base of the ear, where it feeds upon 

 the sap. Ultimately it eats a furrow down the stem to 

 the uppermost joint, or knot, where it assumes the pupa 

 state. As a result, the plant is more or less seriously 

 stunted, the ear being checked in its development, and 

 usually failing to emerge from the sheathing leaves. 

 Farmers call such plants " gouty " ; and Chloi'ops tceniopus 

 is often referred to as the " gout fly." It attacks barley 

 as well as wheat, and is sometimes the cause of very 

 serious loss. 



The third ear in the photograph was taken from a 

 plant which had nourished a larva of the corn saw-fly 

 (Cephus pygmceus). In June the female inserts a single 

 egg into the stem, just below the first or lowest knot, and 

 the larva, when hatched, eats its way steadily upward, 

 often boring through all the knots. When full-fed, how- 

 ever, it descends the stem, and spins its cocoon close to 

 the roots. The ears of attacked plants have a bleached 

 appearance, stand more or less erect, and contain few if 

 any perfect grains. Finally, the whole plant is felled to 

 the ground by the larva, which partially cuts through the 

 stem prior to spinning its cocoon — though what induces 

 this apparently wanton act is not known. The corn 



