The waterbugs or whatever they are have returned in large numbers. I've put more boric acid down in the kitchen, where they're congregating. They're also appearing in large numbers on the front porch. But no place else.
I know I just have to be patient and keep applying the b.a. and eventually they'll be gone for good.
As for the fleas, well the b.a. is supposed to work on them, too. Plus, I went online and ordered a buttload of Frontline for the cats. One thing I've learned from experience is that the most reliable way to get rid of fleas is to keep the cats dosed with Frontline or Advantage. That won't kill all the fleas as quickly as a bomb, but it will kill them all eventually, and I won't have to evacuate the house for a day.