Azenia obtusa - Hodges#9725 (Obtuse Yellow).
Photo: 05/18/16, 10 pm.

Among its grayish brown colleagues, this yellow moth caught my immediate attention. Its larvae have been found on Great Ragweed (Ambrosia trifida), which I (as a mild allergy sufferer) greatly welcome. The wing span of the Obtuse Yellow is about 2 cm. 

bug guide (these photos):