I think what chuckorlando might have meant is that the
male black widow is actually brown with a few markings and at a quick glance can pass for a brown recluse. I'm sure he's not implying you don't know the difference, just that immatures and males (widows) aren't the classic black/red-hourglass critters. Either way, if you're worried about toxic bites then by all means call an exterminator but if the mini-invasion is due to, say, a crack in the house foundation or something then you should also get those sealed up. Take a can or two of GreatStuff and plug any obvious spots like around windows, doors, etc.
To quote burkemuseum.org, "Almost all spiders are venomous; only two small families lack venom glands. The purpose of spider venom is to subdue the spider's prey, almost always insects. In brief, it's an insecticide. Spider venom does not exist to harm creatures, like humans, which are too large for spiders to eat, and in nearly all cases has little if any effect on humans.
A minority of spider species have venom that can cause localized pain in humans, like the venom of bees or wasps. (Bees and wasps are far more dangerous than spiders, however; wasps cause many deaths annually). Of around 50,000 spider species known, only about 25 (1/20 of 1%) have venom capable of causing illness in humans, to a greater or lesser extent. In any given locality you can expect to find from zero to (at most) three such species. These species are called "medically significant" spiders."
There's a pretty good chart
here with a rundown of how bad the bites are and what to do if it happens ... also has a handy "aggression rating".
~Marrow
