You may have seen this phenomenon at one time or another. Little white cocoons on the back of a tomato hornworm. Those cocoons are from the larvae of the Braconid wasp.
New adult Braconid wasps will emerge from those little cocoons!
These amazing ladies and gents are only 1/8th inch long and rely on the caterpillars of many butterflies and moths to perpetuate the species. A fertile female wasp will use her ovipositor (egg laying lance) to lay eggs in the caterpillar of tomato hornworms and other destructive caterpillars.
The life cycle continues over and over again causing destruction of the caterpillars and rewarding us with juicy tomatoes and undamaged plants!!!!