Stemmata Simple eye in invertebrates

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moth larva moult; new stemmata visible behind old head capsule



an example of sawfly larva. has single pair of stemmata, , set higher on head position of stemmata on heads of lepidopteran larvae



the larva of 1 of acherontia species shown here, typical of order lepidoptera. head of larva bears more 1 pair of stemmata, of set low down , far more placed mouthparts



stemmata (singular stemma) class of simple eyes. many kinds of holometabolous larvae bear no other form of eyes until enter final stage of growth. adults of several orders of insects have stemmata , never develop compound eyes @ all. examples include fleas, springtails, , thysanura. strepsiptera have clusters of simple eyes). other arthropoda, such myriapoda, never have eyes other stemmata @ stage of lives.


behind each lens of typical, functional stemma, lies single cluster of photoreceptor cells, termed retinula. lens biconvex, , body of stemma has vitreous or crystalline core.


although stemmata simple eyes, kinds, such of larvae of lepidoptera , of tenthredinidae, family of sawflies, simple in represent immature or embryonic forms of compound eyes of adult. can possess considerable degree of acuity , sensitivity, , can detect polarized light. in pupal stage, such stemmata develop fledged compound eyes. 1 feature offering clue ontogenetic role lateral position on head; ocelli, in other ways resemble stemmata, tend borne in sites median compound eyes, or so. in circles distinction has led use of term lateral ocelli stemmata.



a scolopendra species (chilopoda) stemmata incompletely aggregated compound eyes








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