Iridescence from diffraction structures in the wing scales of <i>Callophrys rubi</i> , the Green Hairstreak

Abstract

ABSTRACT The uniform green colour of the under surface of the wing of Callophrys rubi is due to the integrated effect of the iridescence from a mosaic of polygonal grains, 5.4 μ m. diameter and 1 μ m. thick. The ultrastructure of each grain is a simple cubic network, lattice parameter 0257 μ m. The iridescent colour results from this structure acting as a volume diffraction grating giving a peak reflectance at about 0.548 μ m., green, which is found to be close to the observed reflectance with a peak at 0.550 μ m. measured by a spectrometer.