http://www.photomacrography.net/forum/v ... ight=birch
Each forewing has a thickened basal section, corium, and a distal membranous section (top image).
The rows of spots appear to be mechanoreceptors, specifically Trichoid Sensilla. Each sensillum consists of a thickened ring within a disc connected to a wing vein. - middle image, selective focus. A single hair, the sensillum, projects out from the membrane within the thickened ring - bottom image, selective focus.
These hairs bend in response to air currents, sound and vibration; each hair is innovated by a single nerve. It seems likely that the nerves pass beneath the thickened ring and through the outer disc and into and along the vein to the central nervous system (it's been a while since university days!).
Olympus BHS with 2.5x NFK relay lens, Nikon D600 camera. Top: Nikon 4x obj, others with 40x Oly objective. Zerene Stacker PMax.
