Simple eyes located on top of this wasp's head, between the multi-faceted compound eyes. The next image shows their location a bit more clearly. The simple eyes cannot focus but do detect changes in light intensity, as occurs during sundown and sunup. This triggers the insect's activity patterns - eg some insects are active at night, while others, during the day.
HymenopteraVespidaewaspsimple eyesSmugMug collection