. Class book of economic entomology. Insects, Injurious and beneficial. [from old catalog]; Insects; Insects. Fig, 21. i^iA Cu2 3dA 2dA '^^^ -The hypothetical primitive type of wing venation. Needham.) (After Comstock and through coalescence of adjacent veins, or by the disappearance of veins, as in most moths, flies and hymenopters. The chief longitudinal veins are the costa (C), an unbranched vein on or near the front margin; the subcosta (Sc); the radius (R); the media (M); the cubitus (Cu); and the anal veins (A), typically three but often reduced to one or two. A knowledge of the differen
. Class book of economic entomology. Insects, Injurious and beneficial. [from old catalog]; Insects; Insects. Fig, 21. i^iA Cu2 3dA 2dA '^^^ -The hypothetical primitive type of wing venation. Needham.) (After Comstock and through coalescence of adjacent veins, or by the disappearance of veins, as in most moths, flies and hymenopters. The chief longitudinal veins are the costa (C), an unbranched vein on or near the front margin; the subcosta (Sc); the radius (R); the media (M); the cubitus (Cu); and the anal veins (A), typically three but often reduced to one or two. A knowledge of the different types of venation is very important in classifica- tion. The Comstock-Needham system of terminology is adopted in this Classbook, and students should consult the recent work of Professor Comstock—The Wings of Insects—for a full discussion of the general characteristics of the wings of the several orders of insects. Clothing of the Wings.—While the wings of many insects are naked, many are covered with fine setae, hairs, or scales. The coating of scales is the most distinc- tive feature of the wings of the Lepidop- tera. These scales are modified setae, being evaginations of greatly enlarged hypodermal cells. They are provided with ridges, these serving to increase their rigidity and their protec-. FiG. 22.—Various forms of scales. A, E, Thysanuran (Machilis); B, beetle {Anthre- nus); C, butterfly {Pieris); D, moth {Limacodes).. 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 Lochhead, William, 1864- [from old catalog]. Philadelphia, P. Blakiston's son & co
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectinsects, bookyear1919
