Humidity and heat create perfect living conditions for a number of spiders. Thus far, Texas has only two venomous spiders: the recluse and the black widow. The state does, however, also provide habitats to a number of lookalikes that are often and easily mistaken for a recluse: the wolf spider and the southern house spider. Please note that the spiders, which look like recluses but indeed belong to different species, are not dangerous to humans and should not be killed.
Look in cluttered, dark areas for this venomous spider. There are five kinds of recluses that Texans report finding in their homes and sheds: Loxosceles rufescens, Loxosceles apachae, Loxosceles devia, Loxosceles blanda and Loxosceles reclusa. The latter, also known as the brown recluse spider, is the most common. It is active at night and carries a recognizable upside-down violin shape on its head segment. Note that the recluse does not build webs but actually hunts prey during the night.
Do not mistake the harmless wolf spider---two species, the Hogna and the Rabidosa, are most common---for the venomous recluse. Wolf spiders look like recluses, but they lack the violin shape on the head, and--unlike recluses--are hairy. Like recluses, wolf spiders do not build webs but hunt at night.
Southern House Spider
Look up, and you will find the southern house spider weaving its web around crevices, where it lies in wait for prey to get tangled. Kukulcania hibernalis looks a bit like a recluse but is actually larger and does not have the violin-shaped marking on its head. Female southern house spiders build webs, while the male of the species hunts, much like the recluse or the wolf spider. This spider is not venomous.
Recognize the venomous black widow by its red hourglass-shaped marking underneath the abdomen. Texas is home to four types: Latrodectus geometricus, Latrodectus mactan, Latrodectus various and Latrodectus hesperus. The black widow builds webs, which makes it easier for you to spot it. Remember that this kind of spider is not naturally aggressive but will bite when it feels threatened.