The Golden Tortoise Beetle

In spring and summer, the beetles earn their name when they turn the colour of brilliant liquid gold. But capture one and the gold vanishes and the beetle becomes dirt brown. Here’s why: the colour is produced by an optical illusion; the outer cuticle is transparent and reflects light through a layer of liquid over the next layer of cuticle. The beetles change colour depending on the availability of the liquid layer. In the fall and winter, the beetles become less lustrous and are more orange and bronze with flashes of iridescent colour. If you try and collect the beetle for an insect collection, the beetle soon turns dark brown as is dries, loosing the golden colour.
-EpicLabTime

(via lizardking90)