The adult secondary screwworm, Cochliomyia macellaria, emerging from the puparium.  This newly emerged adult will attain its typical bright green coloration and will be ready for flight in a few hours.  The empty case that it leaves behind will remain in the environment for extended periods of time.  Therefore, a careful search should always be conducted for the presence of the puparium.  Its presence is often useful in establishing the maximum postmortem interval estimation.  Since the puparium is composed of the outer skin of the larvae, many identifying characteristics are retained and a species identification may be obtained even though the adult fly is not recovered.