Kimberlee
Your photo is of a looper, family Geometridae. There is not a looper caterpillar that only feeds on tomatoes. The cabbage looper is known to feed on tomatoes besides cabbage family, as well as basil, so that is probably what yours is. The caterpillar turns into a brownish moth.
The cabbage looper usually does not cause major damage to tomatoes, however if it you have a lot of them, you could spray with Bt. Bacillus thuringensis is a bacteria that only affects caterpillars. Tho this is organic you do not want to spray it near beneficial caterpillars or those of the big silk moths. This will control the caterpillars not the cocoons. Please read the label for application directions.
