Hobo spiders, like this young female, have never been known to cause medically significant injuries in Europe. But in North America, hoboes have been blamed for serious symptoms and a few deaths.

January 1988: A 56-year-old woman from Spokane, washington, feels something bite her on the thigh. She soon becomes nauseated and develops a migrainelike headache. Her thinking becomes addled. In the days that follow, a patch of dead tissue sloughs from the spot where she was bitten. It is at least two weeks before she seeks help, and by then it is too late. She is bleeding from the orifices, even from the ears. Doctors find her blood deficient in several basic components. Her marrow stops making red blood cells. After lingering in the hospital for several weeks, the woman dies of internal bleeding.

There are other cases.

October 1992: A 42-year-old woman from Bingham County, Idaho, feels the burning bite of a spider on her ankle. She, too, develops a headache and nausea, as well as dizziness. The bite blisters and bursts, leaving an open wound that continues to grow. After 10 weeks, the crater, still growing, is big enough to accommodate two thumbs and is ringed with black flesh. More than two years after the bite, the wound heals as a sizable scar, beneath which veins are clotted. The woman’s ability to walk and stand remains impaired. The spider she found crushed within her clothing was a hobo spider, Tegenaria agrestis, a member of the family Agelenidae.


Agelenids are found in temperate places all over the world, in about 38 genera and 500 species. The hobo spider first appeared in the United States sometime before the 1930s. It spread across the Pacific Northwest and adjacent areas of Canada by attaching its egg sacs to shipping crates that were loaded on trains, hence its name. Its genus name, Tegenaria, means “mat weaver”; its species name, agrestis, suggests the agrarian life it leads in Europe. But in North America the hobo spider can often be found in cities and has made its presence known in ways its European experience never suggested.

AN INTERNATIONAL ROGUES’ GALLERY

Black widow

(Latrodectus mactans)

The venom of the black widow contains a nerve toxin that produces excruciating pain throughout the body. It can kill frogs, snakes, cats, horses, and, occasionally, humans.

Giant house spider

(Tegenaria gigantea)

People have nothing to fear from the formidable-looking giant house spider, but its cousin the hobo spider does. The giant preys on the hobo and may help keep it out of houses.

White-tailed spider

(Lampona cylindrata)

Doctors previously believed that this Australian spider caused necrotic lesions in the people that it bit. Recent evidence suggests, however, that the white-tailed spider is harmless.

Camel spider

(Arachnida, Solifugae)

The world’s fastest moving arachnid packs no venom at all, relying on its massive mouthparts to kill insects mechanically. Still, scary rumors about it continue to spread.

Brown recluse spider

(Loxosceles recluse)

This unobtrusive spider can cause necrotic lesions in some people. Doctors often blame it for injuries that may have been caused by the hobo spider instead.

 

Yellow sac spider

(Cheiracanthium inclusum)

Common in North America, this quarter-inch-long spider spends the day in a silken retreat and hunts by night. When it bites humans, it can leave hard, red sores with white pustules.