. An introduction to zoology, with directions for practical work (invertebrates). 256 INTRODUCTION TO ZOOLOGY to be seen clinging to the end of the body. The two back pairs of legs are short but broad, fringed with hairs, and are used in swimming, the front pair being used for holding. In the male the tarsal joints are enlarged. These beetles feed on water plants and minute water insects, and they hiber- nate on the mud at the pond bottom. Eggs are laid in the spring on some sub- merged plant, and the larvae hatch within a fortnight; they may be but little more than half an inch long, and each
. An introduction to zoology, with directions for practical work (invertebrates). 256 INTRODUCTION TO ZOOLOGY to be seen clinging to the end of the body. The two back pairs of legs are short but broad, fringed with hairs, and are used in swimming, the front pair being used for holding. In the male the tarsal joints are enlarged. These beetles feed on water plants and minute water insects, and they hiber- nate on the mud at the pond bottom. Eggs are laid in the spring on some sub- merged plant, and the larvae hatch within a fortnight; they may be but little more than half an inch long, and each has a head and twelve segments. The three thoracic segments bear ordinary jointed legs, and each of the first eight abdominal segments bears a pair of delicate feathered "tracheal gills," while the last segment bears two pairs of such gills. The larva is carnivorous, but will at times feed on water plants. It swims actively with a serpentine motion. After a while it leaves the water, and is said to pupate on some plant which grows above the water surface, spinning for itself a little silk cocoon well hidden amongst the foliage and very rarely seen. The imago emerges in August or Fig. 188.âThe Larva of the Whirligig Beetle. Sub-order 3 : Serricomia. Garden Beetles with Serrate Antennae. In the family of the Skipjacks, or Click Beetles Click Beetles (â ^^*'^"^**)> the form of the antennae is very variable. It may be serrateâmade up of little triangular pieces, which project most on the inner side of the antennaâbut it is thread-like in just a few beetles which, how- ever, because of their resemblance in other points, are also classed here. A curious feature in the anatomy of Click Beetles is the elongation of the first segment of the thorax on its under side into a central spine (Fig. 189, s), which points backwards and fits into a groove in the second segment. If the beetle is put on its back, it arches up its body. Please note that these image
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Keywords: ., bookcentury1900, bookdecade1910, bookpublisherlondo, bookyear1913
