Waterbugs!

[Greenciti]

Get Boric Acid powder and spinkle it everywhere you have seen them. It causes them to suffocate when they walk through it. It is non-toxic to animals if you have any around. You can find it at just about any home improvement store.

[CarrieNeno]

In our old house, we had them come up through our basement drain straight from the sewer system. Though it was only during the warmest wettest month of summer (Aug). We reaffixed our drain, adding mesh and SEVERAL times per day flushed massive amounts of steaming hot water down the hole. Seemed to do the trick. So, so gross either way though, I know.

[SouthCityGal]

I wonder if the OP ever solved her problem. One of my homes (see below) had a roach problem. Our exterminator would put some kind of granular outside the parameter of the house. I'm assuming that would work with waterbugs, too. This helped significantly, but we'd still come across dead ones occasionally. While we could prevent them from living in our basement, we couldn't stop them completely from coming inside to die.

As a city dweller all my life, here's my experiences:
1st home: North Hampton area--lots of waterbugs, centipedes and spiders but, surprisingingly, never any roaches
2nd home: Holly Hills area--never any waterbugs, but tons of roaches (the reddish brown ones), with occasional centipedes and spiders
3rd and current home: North Hampton--no waterbugs, no roaches, and hardly anything else in our basement (knock on wood)

I would attribute the most bugs to the homes with dreary and/or wet basements. So waterproofing, sealing up holes, and maybe even running a de-humidier might help.

[BoomBoxing]

Never had any bugs in my house in North Hampton either. But my old apartment in south county had a bad brown recluse problem. I hate hate hate those nasty things!