Answer: Aphids are small soft bodied sucking insects that tend to congregate in the growth tips of plants. They can be treated with insecticidal soap or knoscked off with a stream of water from the garden hose. Based on your description it does not sound like aphids in this case. It might be the larvae of a beetle of some kind or some type of moth or butterfly. You can try a neem based spray or, if it is truly a caterpillar, Bt (Bacillis thuringiensis). Hand picking may also be effective if you only have a few plants.
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