. Elementary text-book of zoology. Zoology. 586 INSECTA. which, however, they leave in some cases the last segment (pyyi<l't«n<), or in other cases (Staphytince) several segments, exposed. As a rule, when the insects are at rest, the straight internal edges of both wing-covers are shut closely together, while the outer edges are "bent round the sides of the abdomen. Sometimes the inner edges of the wings are fused together, so that the power of flight is abolished. In rare cases the wings are altogether absent. The head is seldom free, but as a rule is sunk into the freely moveable
. Elementary text-book of zoology. Zoology. 586 INSECTA. which, however, they leave in some cases the last segment (pyyi<l't«n<), or in other cases (Staphytince) several segments, exposed. As a rule, when the insects are at rest, the straight internal edges of both wing-covers are shut closely together, while the outer edges are "bent round the sides of the abdomen. Sometimes the inner edges of the wings are fused together, so that the power of flight is abolished. In rare cases the wings are altogether absent. The head is seldom free, but as a rule is sunk into the freely moveable prothorax, and bears very variously shaped, usually eleven-jointed, antennae. In the male the latter are of considerable size and have a considerable extent of surface. Ocelli are with few exceptions absent, but the facetted eyes are only absent in certain blind species, which live in caves. The mouth parts are adapted for masticating and biting, and sometimes show transi- tional forms to those of the Hyiiwnuptem. The maxillary palps are usually four- jointed and the labial palps three-jointed. In the predatory beetles, the external lobe of the maxilla has a palp-like form and articulation. The labium, which is sim- plified by the reduction of its parts, is in rare cases elongated to form a divided tongue. The large prothorax (cervical shield) is moveably articulated with the mesothorax, which is usually weakly de- veloped ; and on it, as well as on the FIG. 484.—a, Cieindela campestris , , i, c, its larva with the two dorsai otiier thoracic segments, the pleura ex- hooks on the fifth abdominal tend on to the sternal surface. The segment (regne animal). legs vary very much in shape, but usually end with a five-, rarely with a four-jointed tarsus. The tarsus is rarely composed of a smaller number (from one to three) of joints. The "abdomen is attached to the metathorax by its broad base, and always possesses a greater number of dorsal than of ventral plates, of which som
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Keywords: ., bookcentury1800, bookdecade1880, booksubjectzoology, bookyear1884
