Although stemmata are simple eyes, some kinds, such as those of the larvae of Lepidoptera and especially those of Tenthredinidae, a family of sawflies, are only simple in that they represent immature or embryonic forms of the compound eyes of the adult. They can possess a considerable degree of acuity and sensitivity, and can detect polarized light. In the pupal stage, such stemmata develop into fully fledged compound eyes. One feature offering a clue to their ontogenetic role is their lateral position on the head; ocelli, that in other ways resemble stemmata, tend to be borne in sites median to the compound eyes, or nearly so. In some circles this distinction has led to the use of the term "lateral ocelli" for stemmata.