Strangely enough, the one really dangerous spider on the American continent is small, obscure, and practically unknown to popular or journalistic hysteria. Latrodectus mactans is its scientific name. It is about the size of a large pea, black with a red spot on the back -- a useful danger signal -- and spins a small web in outhouses or around wood-piles. So far as is known, its poison is the most virulent and powerful, drop for drop, secreted by any living creature. Cobra virus, in the minute quantity which the Latrodectus's glands contain, would probably have no appreciable effect upon man; whereas the tiny spider's venom, in the volume injected by the cobra's stroke, would slay a herd of elephants. Were this little-known crawler as large as the common black hunting spider of our gardens and lawns, its bite would be almost invariably fatal. Happily, the "red-spot's" fangs, being small and weak, can with difficulty penetrate the skin, and are able to inject venom in dangerous quantity only when the bite is inflicted upon some tender-skinned portion of the body. Nevertheless, fatalities consequent upon the bite of this insect are sufficiently well attested to take rank as established scientific facts.

   One of the most detailed comes from an intelligent farmer of Greensboro, North Carolina. A workman in his employ, while hauling wood, brushed at something crawling upon his neck and felt a sharp, stinging sensation. He found a small, black spider with a red spot. This was at 8.30 A.M. Presently, ten small white pimples appeared about the bitten spot, though no puncture was visible and there was no swelling. The pain soon passed, but returned in three hours and became general, finally settling in the ab............