They aren't moving and don't seem to be attached, as the come off easily when I wipe the leaves with a tissue. They are on two plants that were right next to each other but not the basil that was also next to one of them
They're pretty easy to manage. Just make a solution of dish soap in water (~1 tsp per L) and spray the plants. It dissolves their waxy coating and kills them quick. It shouldn't harm the plants but spray a test area first to be sure. It won't harm their eggs so you'll probably have to spray a few times.