. Elementary entomology. Insects. 228 ELEMENTARY ENTOMOLOGY Gall-gnats. The smallest and most deli- cate of the gnatlike flies are the gall-gnats (Cecidomyiidac). The adults are rarely over one eighth of an inch long, with long antennae clothed with short hairs, and with the wing-veins greatly reduced in number. They will be rarely noticed by the begin- ner, but the work of the larvae is often much in evidence, owing to their feeding within the stems and leaves of plants and giving rise to galls. Frequently a green, cone-shaped gall is found on the tips of willow twigs, known as the pine-cone
. Elementary entomology. Insects. 228 ELEMENTARY ENTOMOLOGY Gall-gnats. The smallest and most deli- cate of the gnatlike flies are the gall-gnats (Cecidomyiidac). The adults are rarely over one eighth of an inch long, with long antennae clothed with short hairs, and with the wing-veins greatly reduced in number. They will be rarely noticed by the begin- ner, but the work of the larvae is often much in evidence, owing to their feeding within the stems and leaves of plants and giving rise to galls. Frequently a green, cone-shaped gall is found on the tips of willow twigs, known as the pine-cone willow-gall, which is caused by one of FIG. 359. Pear midge (Di- „ . , .. ., x plosispyrivord). (Enlarged) these larvae (Cccidomyia strobiloides]. (After Riiey) The larvae of the clover-seed midge live in the heads of clover and destroy the seed so that in many sections it is often impossible to mature it. The best-known exam- ple of the family, an d our worst wheat pest, is the Hessian fly, so called be- cause it was sup- posedly introduced in straw brought over to Long Is- land by the Hes- sian troops during the Revolutionary War. The mag- gots bore into the crown and stalks of wheat, weaken- ing the plant and seriously curtailing production where. FIG. 360. The Hessian fly, adult male. (Much enlarged) they are abundant. (After Marlatt, United States Department of Agriculture). Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Sanderson, Dwight, 1878-1944; Jackson, C. F. (Cicero Floyd), b. 1882. Boston, New York [etc. ] Ginn and Company
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