This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1917 Excerpt: ... a circle (Plate xxxi, 5-10). It may continue with the genae an unbroken lower outline of the face, or may project far below the genae to form a long extension (Plate xxxi, 15, 24). This variation has been used as a specific character in certain American genera, particularly Ceresa and Stictocephala (Van Duzee, 1908a ...
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This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1917 Excerpt: ... a circle (Plate xxxi, 5-10). It may continue with the genae an unbroken lower outline of the face, or may project far below the genae to form a long extension (Plate xxxi, 15, 24). This variation has been used as a specific character in certain American genera, particularly Ceresa and Stictocephala (Van Duzee, 1908a:42-43). Occasionally the outer margins of the clypeus are covered by the overlapping projections of the vertex (Plate xxxi, 21, 23); again, the vertex may be prolonged to a point below the clypeus. When such characters are present they have invariably been found good for systematic work. In fact the relation in position between the clypeus and the lateral margins of the vertex (the "cheeks" of the older writers) has been often noted as an excellent character in taxonomic tables. The clypeus is much inclined to pubescence and the tip is usually decorated with stiff hairs or bristles which partly cover the base of the labium. The frons is not represented as a distinct sclerite in the Membracidae. In certain forms, however, a vestigial segment which apparently represents this sclerite may occasionally be found between the vertex and the clypeus (Plate xxxi, 24-27). This has never been found as a constant, clean-cut, and well-marked sclerite, but numerous suggestions of its presence are offered, chiefly in nymphal material. Curiously enough the evidence is not limited to a single subfamily but is scattered thru widely separated genera. It seems reasonable to suppose that in the more primitive forms of insects the frons is present and bears the middle or the anterior ocellus. Comstock and Kochi (1902:14) state: "In the more generalized insects at least, if not in all, the front bears the median ocellus." Crawford (1914:5) notes, ...
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