I think your cat could be one of two moths, both related to woolly bears, Konrad - either the great tiger moth/arctia caja or the St. Lawrence tiger moth/platarctia parthenos. Wagner says of the great tiger moth - "Larvae to 6 cm. St. Lawrence tiger moth similar in size and distribution, readily distinguished by its more uniformly dark coloration, brown spiracles, and warty setal tufts." He also says, "This densely hairy behemoth is the entomological equivalent of a musk ox. It is a denizen of northern latitudes and alpine habitats that is rarely encountered south of our northern tier of states. Although eggs are easily obtained, rearing this species can be a challenge to even the most attentive caterpillar wrangler because the middle instars enter a sustained diapause and require an extended period of low temperatures (winter) before they will complete their development in the spring." I couldn't find a picture of a St. Lawrence tiger moth cat, just a great tiger moth - based on all the red showing in this picture, I'd say yours is most likely the St. Lawrence type. MissSherry Here is a link that might be useful:

I don't know what they are, but spraying the plants with BT will take care of any kind of caterpillar. Just go to the garden center and ask for BT. They'll know what you're talking about. It comes as a liquid or a dust. Since those are on the undersides of the leaves, you'll need the liquid so you can spray the backs of the leaves as well as the front. Deanna

oops. Wants me to sign in. Beyond that, was it damaging your tomatoes? If not, leave it be.

I have caterpillar's that look similar, in that they have no obvious legs. But some are brown (slightly striped) and some bright green. They are eating leaves voraciously in my greenhouse and the basil in particular is struggling to grow faster than it is being eaten. I remove a kill as many as I can find but especially the green ones are hard to spot. It's now only August and some of the links above suggested that these larvae are only laid in late summer, and I've had the problem since July, and maybe earlier (but i first guessed slugs as i have lots of those too but pellets have more or less one that battle for the moment) HB