Stigma

[Kenelm Philip]

	Sharyn Fernandez inquired about butterfly stigma, and wanted ref-
erences. Pages 54-59 of 'The Butterflies of North America' by James Scott
discuss androconial scales ('scent scales') in some detail. A stigma is
simply a patch of androconia--in some butterflies these scales are grouped
into one or more clearly visible stigma, while in others they are scattered
over the wing surface.
	
	Androconia are specialized scales which release odors (pheromones)
that play a role in courtship. Under a microscope they appear different
from 'normal' wing scales. Some have brushlike tips--others merely lack the
serrated ends found on other scales.

	The presence of a stigma can indeed be used to show that a butterfly
is a male, in those species that have them (some skippers, a few _Colias_,
many Satyrids, etc.) for that sex only.

							Ken Philip
fnkwp at uaf.edu