72 ECONOMIC ENTOMOLOGY 



Heads: 



(a) Heads turn white and grains are shrivelled or imperfectly filled. — Wheat 

 Stem Maggot {Meromyza americana) and American Frit-fly {Oscinis car- 

 bonaria), p. 261. 



(b) Heads shrivelled and blighted, and imperfectly filled; the presence of 

 orange-colored maggots. — Wheat Midge (Diplosis iritici), p. 249. 



(c) Heads covered with green plant-lice. — Grain Louse {Aphis avetice), p. 142. 



(d) Heads turn white; minute dots or lines on leaves usually run parallel 

 with the veins and remain white; the work of minute insects. — Grass Thrips 

 (Anaphothrips striatiis), p. 119. 



(e) Spotting of the leaves, spots whitish at first, turning brown or black. — 

 Six-spotted Leaf-hopper {Cicadula 6-notata), p. 154. 



(/■) Heads blasted and stems withered; the presence of frothy masses on the 

 stems. — Grass-feeding Froghop per {Philcenus lineatus), p. 153. 



II. INSECTS INJURIOUS TO INDIAN CORN OR MAIZE 



(Consult Bull. 44 Illinois Agric. Exper. Station) 

 Planted Seed: 



(a) Plant fails to come up after planting; grain destroyed by a maggot which 



eats out the interior. — Seed-corn Maggot {Phorbia fusciceps), p. 277. 

 {b) Plant fails to come up, or the young plant suddenly wilts after it is above 

 ground; the presence of hard, smooth, yellowish, wire-like worms. — 

 Wire-worms spp., p. 293. 

 Roots: 



(a) Young plants killed or withered; roots eaten. — White Grubs or Wire-worms, 



P- 303- 



(b) Young plants unequal in growth; roots dwarfed without external injury; 

 presence of ants. — Corn-root Louse {Aphis maidi-radicis) . 



Stalks: 



{a) Plants cut off near surface of ground. — Cutworms, p. 185. 

 {b) Plants unthrifty and covered with greenish plant-lice. — Corn Plant-louse 

 {Aphis maidis), p. 142. 



(c) Stalks punctured and slit. — Corn Bill Bugs {Sphenophorus spp.), p. 338. 

 {d) Pith of stalk and pedicel of cob tunneled by a flesh-colored caterpillar, 



terminal internode broken. — European Corn Borer {Pyrausta nubilalis). 

 Leaves: 



{a) Leaves thickly covered with green plant-lice. — Corn Plant-louse {Aphis 

 maidis). 



{b) Leaves eaten. — Army-worm {Cirphis unipuncta) and Grasshopper, p. 190. 



(c) Leaves perforated by round or oblong holes arranged in parallel trans- 

 verse rows. — Corn Bill Bugs, p. 338. 



{d) Leaves wilted and brownish, sometimes sickly and whitish; the presence of 

 small red and larger black-and-white bugs. — Chinch Bug {Blissus leuco- 

 pterus), p. 161. 



(e) Leaves wilted and brownish caused by the maggot of a syrphid fly. — 

 Corn-feeding Syrphid Fly {Mesogramma politus), p. 251. 



