. Coleoptera. Beetles. 392 NATURAL HISTORY OF ARTHROPODS. occur, however, in hot springs, and Hooker writes of a Himalayan species that was found abundantly in springs which had a temperature of 112° F. Insects of this family respire, when under water, a sujiply of air which they carry beneath their elytra, and which they renew, from time to time, by coming to the surface, and resting with the head hanging and the tij) of the abdomen just at the surface of tlie water. Some of them remain submerged an hour and a half, before renewing their supjjly of air. The larger sj)ecies of Dytiscidie often
. Coleoptera. Beetles. 392 NATURAL HISTORY OF ARTHROPODS. occur, however, in hot springs, and Hooker writes of a Himalayan species that was found abundantly in springs which had a temperature of 112° F. Insects of this family respire, when under water, a sujiply of air which they carry beneath their elytra, and which they renew, from time to time, by coming to the surface, and resting with the head hanging and the tij) of the abdomen just at the surface of tlie water. Some of them remain submerged an hour and a half, before renewing their supjjly of air. The larger sj)ecies of Dytiscidie often attack small fishes. The larvffi of the Dytiscidie, wliich are aquatic in habits, and have free mouth-jiarts, five-jointed thoracic legs, four-jointed antennje, and six pairs of ocelli, are especially noticeable because their mandibles are hol- low, and are consequently ada])ted both for seizing their prey and for sucking out its juices. The mouth cavity between the mandibles is not, as is often as- serted, entirely closed. The resjiii-e by means of two stigmata at the posterior end of the abdomen. Cybister has the suckers on the under side of the tarsal disc alike, and arranged in four rows. C. fim- briolatus, from the eastern United States, is greenish black, margined with yellow, and is about inches long. In Dytisais the suckers of the tarsal disc are of different sizes, and the posterior stigmata are larger than in ('i/bisier ; the species are all large. D. fasciventris, a species about inches long, is common in Xew England, and D. verticalis, about inches long, is not very rare in the same region. Both are black, with yellow lateral margins of the prothorax and elytra. In Europe D. viar- ginalis, a species about the size of D. fasciventris, is the common one, and its larvje attack young frogs, tritons, and fishes. The species of Acilius are of medium size, and have the posterior tarsi ciliate, the claws of the same tarsi equal or nearly so. Many of th
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Keywords: ., boo, bookcollectionbiodiversity, booksubjectbeetles, bookyear1884
