Male Coenagrionid damselfly colors are visual signals of sexual identity that may reduce harassment of males by other males.  Intraspecific visual signals should be maximally conspicuous under the specific light environments where animals interact. This prediction was tested by comparing reflectance and radiance spectra from eight species of Enallagma damselflies with spectra from the visual backgrounds of their respective microhabitats. Female spectra were analyzed from three species.  Males from each species were highly conspicuous within their respective light environment.  Males flying midday over open water all exhibited blue colors that were bright under ambient daylight and exhibited the greatest contrast with the pond surface. Males that flew late in the afternoon or at dusk reflected longer wavelengths than species active at midday.  Red males that perched consistently on vegetation exhibited high contrast with the green vegetation. Females that exhibited high contrast values were andromorphic.