DESCRIPTION: L= 0.75" (19mm).  All brown with difficult-to-see, violen-shaped marking right behind eyes. Brown Spiders have only 6 eyes (unlike most spiders which have 8), and the eyes are arranged in three pairs (see Vetter 1999 for more information).
NATURAL HISTORY: Dangerously Venomous (potentially fatal -- when bitten, call the Arizona Poison and Drug Information Center at 626-6016 in Tucson and 1-800-362-0101 elsewhere in Arizona.). The venom generally causes a sore that enlarges over time (see picture to right) and may cause permanent tissue damage (and possible death) if not treated by a physician (see Vetter and Visscher 1998 for more information). Brown spiders use irregular webs built underneath rocks and debris to catch their arthropod and other invertebrate prey.

Don't confuse the dangerous Brown Spider with the harmless Wolf Spider (Hogna carolinensis). Wolf Spiders have 8 eyes instead of 6 and often are larger and stockier than Brown Spiders. Also Wolf Spiders have a lighter, peach-colored stripe down their cephalothorax (combined head and thorax) compared to the darker, brown, fiddle-shaped marking on the cephalothorax of the Brown Spider.