Volume 8, Plate IV / Entomology (Insects)

Dytiscidæ

1. Dytiscus dimi­diatus. Brownish black tinged with green, with yellow antennae and upper lip and a rust-red crescent spot on the forehead, the thorax broadly yellow-margined and a yellow stripe running the whole outer edge of the elytra. The smooth male elytra bear three rows of punctures, the under side and legs yellowish with black breast sutures; it has occurred at Cambridge and in some other parts of England.
2. Gyrinus natator. Nearly three lines long, of an ovate form, blue-black with a highly resplendent metallic lustre, the thorax marked with three transverse lines on each side and a narrow elongate triangular scutellum. The convex elytra have eleven striae of minute punctures and a yellowish inturned margin, the breast pitch-red and the legs ferruginous; it gambols in small parties on still water from spring, diving when alarmed and reposing in mud through winter.
3. Cyclous vittatus. About nine lines long and five broad, bluish black slightly glossed with purple with faint coppery reflections, the whole surface highly polished, the purple and blue forming bands on the elytra in life. The under side is pitch brown with paler swimming legs and very long brownish-black fore-legs, and it lacks an apparent scutellum; it was received from Java.
4. Hydrous piceus. Black inclining to olive, the elytra margins faintly tinged with green and purple, the antennae and mouthparts reddish, each wing-case marked with eight dotted lines, the breast clothed with yellowish hair and yellow spots along the abdomen. It is the largest aquatic beetle of Britain, common in the south but absent from Scotland; less rapacious than the Dytisci as an adult, but its larva is so bloodthirsty it is called ver-assassin in France.