. Economic entomology for the . Heart of a stag-beetle, showing the wings and chambers : at the side, the interior of a chamber, to show the valves. Insects have no system of arteries and veins, and only one real blood-vessel, which serves also as the heart. This, as has been

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Keywords: ., bo, bookcentury1800, bookdecade1890, bookpublishernp, bookyear1896