It's #TabanidTuesday
Here are 2 examples of the eyes of horseflies. The bands are not pigments of colour but caused by the light refracting on the tiny 'nipples' on each of the ommatidia - the individual eye units.
After death the eyes shrink through dessication and so the unique patterns disappear.
#tabanidtuesday #tabanidae #eyes #morphology #horsflies #flies