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Brown Recluse Spider (Poisonous) Brown Recluse Spider, common name for a small brownish spider found mainly in the central and southern United States. Also known as the violin spider, it is characterized by a distinct violin-shaped patch on its cephalothorax (head and midregion). Except for the black widow spider and certain related species, the brown recluse spider is the only United States spider whose bite can be dangerous to humans. Most adults are about the size of a United States dime to a US quarter with legs extended. It spins a sheet web that may be found in secluded areas among rocks or in houses. The bite causes a long-lasting sore that involves tissue death, and severe reactions to it may become life-threatening. The spider may live more than ten years. The feature that most distinguishes the brown recluse from many other harmless spiders is a somewhat darker violin-shaped marking on top of the leg-bearing section of the body. The neck of the violin "silhouette" points towards the rear (abdomen) of the spider. Brown recluse spiders have 3 pairs of eyes arranged in 3 groups of two rather than 4 pairs for most other spiders. Use of a 10x hand-lense is needed to see eye groups (top photo). The brown recluse roams at night seeking its prey. During the day, it hides in dark niches and corners, where it may spin a poorly organized, irregular web. Eggs are deposited in 1/2 inch long off-white silken egg sacs, often appearing flattened beneath and convex above. It is shy and will try to run from a threatening situation but will bite if cornered. People are sometimes bitten while they are asleep because they roll onto a brown recluse spider while it is hunting in the bed. More often the victim is bitten while putting on a shoe or piece of clothing which a spider has selected for its daytime hiding place. The bite of the brown recluse is usually painless until 3 to 8 hours later when it may become red, swollen, and tender. Later the area around the bite site may develop into an ulcerous sore from 1/2 to 10 inches in diameter. Healing often requires a month or longer, and the victim may be left with a deep scar. Prompt medical attention can reduce the extent of ulceration and alleviate other complications that may develop.Spider bites are difficult to diagnose, even by physicians. Anyone bitten by a spider which is believed to be a brown recluse should try to collect the specimen and bring it to a qualified individual for identification. Positive identification by an expert will help the physician decide on the appropriate course of treatment.
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