Found nectaring in the morning on flowers of Chamaebatiaria millefolium. Habitat is the volcanic tableland on east side of the Long Valley caldera with the dominant vegetation being sagebrush (Artemisia tridentata) and well-spaced Jeffrey Pines (Pinus jeffreyi).

Placement of cross-vein "rm" relative to the discal cell and antennal segment proportions indicate genus Physoconops, and the overall black color and distinctive (near-apical) hyaline interruption of the anterior infuscation of the wing indicate species sylvosus.