The brown recluse spider is mainly found in the Midwest and southern parts of the United States. However, there is another type of recluse spider that inhabits the Southwest, including the deserts of California, and is often mistaken for the brown recluse. This spider is known as the desert recluse and has similar characteristics, but some differences as well.
For instance, the desert recluse is also yellowish or tan in color and measures approximately 0.5″ in body length. However, the desert recluse has longer legs than the brown recluse and its legs and body together can span 1-1/2 to 2 inches. Males and females tend to be about the same size. Like the brown recluse, the desert recluse has six eyes arranged in three pairs in a semi-circle pattern. On this particular species of recluse spider, the trademark fiddle shape is very faint by comparison or absent entirely.
Like its brown recluse relative, the desert recluse has a toxic bite that can result in large sores and skin lesions. The desert recluse is the most common type of recluse spider found in California and tends to inhabit the Mojave and Sonoran Deserts. This spider can also be found in Arizona, Nevada, New Mexico, Texas, and Utah.
There are a few other known species of recluse spiders found in the United States in addition to the brown and desert recluse. These include the Arizona recluse (Loxosceles arizonica), which is found in Arizona, and the Mediterranean recluse (Loxosceles rufescens), believed to be introduced from the Mediterranean region, now found sporadically throughout the United States. Two other species are known by their scientific names, the Loxosceles devia, found in southern Texas, and the Loxosceles laeta, found in southern California as well as Massachusetts.
(The brown recluse and desert recluse are known as Loxosceles reclusa and Loxosceles deserta, respectively.)