Fig. 1. Composite images of (A) non-polarized (Danaus erisimus) and (B) polarized (Memphis chaeronia) butterfly wings. Two pattern elements in B are polarized while none are polarized in A. The few instances where polarization exists in A are due to wear on the wings and the shine of the wing veins. False color imaging allowed transformation from a continuous to a binary polarized data set. Color reference keys: blue indicates no polarization while green, yellow, red and white indicate increased polarized reflectance (white=complete polarization).