Figure 4
External characteristics of larval stemmata and developing adult compound eyes during the immature stages of the whirligig beetle. A-C: The morphology and disposition of six stemmata of one side of the head in each of the three larval instars (1st -3rd in). Stemmata 1 and 2 become comparatively larger and stemmata 5 and 6 become comparatively smaller in the 3rd instar. D-I: During pupation, the larval stemmata gradually degenerate and the adult upper and lower compound eyes (uComp and lComp Eye) are gradually formed on the dorsoposterior and ventroposterior side of the larval stemmata. P1-13, day 1–13 of pupation at room temperature.