You’ve noticed them crawling from under rocks, vegetation or even the couch in the living room. The beetles that seem to have appeared out of nowhere in annoying numbers are black ground beetles. They are harmless, and even beneficial to agriculture by feasting on other harmful insects. “They’re not dangerous,” said Mackie Nelson, Jr., owner of M & M Exterminators. “They might bite if you handle them. They’re just a nuisance. They’re just coming from outside.” There are thousands of kinds of ground beetles. Some are black and others are iridescent. The insects usually come out during the summer months between June and August.