. A text-book of agricultural zoology. Zoology, Agricultural; Zoology, Economic. DIPTEKA OE TRUJS FLIES. 195 DIPTERA, OR Tbdb Flies. The Diptera form the last order of insects with a complete metamorphosis. They can easily be identiiied by the presence of a single pair of wings only—the pos- terior or second pair being reduced to two club-shaped processes called " balancers,'' " halteres," or " poisers " (fig. 90). The two anterior wings are fiat membranous Fic- 'jo.—Halteee or Fly. expansions, never covered with scales, although they are sparsely present in gnats (Gul
. A text-book of agricultural zoology. Zoology, Agricultural; Zoology, Economic. DIPTEKA OE TRUJS FLIES. 195 DIPTERA, OR Tbdb Flies. The Diptera form the last order of insects with a complete metamorphosis. They can easily be identiiied by the presence of a single pair of wings only—the pos- terior or second pair being reduced to two club-shaped processes called " balancers,'' " halteres," or " poisers " (fig. 90). The two anterior wings are fiat membranous Fic- 'jo.—Halteee or Fly. expansions, never covered with scales, although they are sparsely present in gnats (Gulicidce) (fig. 91) and a few gall-flies (Ccridumijidie). Hairs are often present on. A Gnat {(.'ulex annnlaius). Head of Gnat (Pierc-ing mouth). A, Piercing lancet; LI, lower lip : Ul, uijper lip ; iVfd, mandible ; Mx, maxilla ; Lp, labial palp. the wings, both upon and around them. Some Diptera, such as the Fleas (Pulicidce), fig. 117, and the Sheep-ticks (Melophar/a), fig. 116, are entirely apterous. In regard to the mouth parts of. 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 Theobald, Frederick Vincent, 1868-1930. Edinburgh and London, W. Blackwood and Sons
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectzoology, bookyear1899
