. An introduction to zoology, with directions for practical work (invertebrates). 282 INTRODUCTION TO ZOOLOGY CHAP. All the four genera of Heteroptera so far mentioned have been alike in living a submerged life, and in having small and concealed antennae. Those now to be described {Hydro- metra, Gerris, and Velio) all have long and conspicuous antennae, and they live on the surface of the water, running or jumping actively over the surface film, though occasionally penetrating it to dive below. Series B. Forms living on the surface of the water and having conspicuous long antennae. The Pond-sk
. An introduction to zoology, with directions for practical work (invertebrates). 282 INTRODUCTION TO ZOOLOGY CHAP. All the four genera of Heteroptera so far mentioned have been alike in living a submerged life, and in having small and concealed antennae. Those now to be described {Hydro- metra, Gerris, and Velio) all have long and conspicuous antennae, and they live on the surface of the water, running or jumping actively over the surface film, though occasionally penetrating it to dive below. Series B. Forms living on the surface of the water and having conspicuous long antennae. The Pond-skater (Gerris). The little narrow-bodied, long-legged Pond-skaters are very numerous on the water surface, over which they slide, or sometimes progress in a series of leaps. Occasionally they dive below the surface, when the hairy body is seen to have a silvery air-film covering it. The four-jointed an- tennae are so long as to look almost like an extra pair of legs. The first pair of legs are held forwards and used for prehension. By the lengthening of the first segment of the thorax, this pair is widely separated from the second pair, which is that chiefly used in loco- motion, the hind -pair serving to guide the movements. As in all water-bugs, this genus has a long beak with which the food is pierced and its juices extracted. It feeds very largely on dead and dying insects that fall on to the surface of the water. The adult insects are nearly half an inch long, but are not all alike. Some have only short wings, and are incapable of flight, whilst others have well- developed upper horny wings and lower membranous ones with which they can Fio. 208.—The Pond-skater (Gerris). Larva above, adult below—winged variety. (Real lengtb shown by the lines to the left.). 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 origi
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Keywords: ., bookcentury1900, bookdecade1910, bookpublisherlondo, bookyear1913
