Question Marks closely resemble Eastern Commas, but look for the fourth "flattened dot" at the end of the row of three dots. Question Marks have this fourth flattened dot; Eastern Commas almost never do (except in rare cases). Question Marks are also slightly larger on average, but there is some overlap in their size range.
This is the "umbrosa" or summer form of the Question Mark butterfly. Notice how the lower wings are dark black, as opposed to the lighter winter forms above.
Ventral view of a Question Mark butterfly. The small white marking on the undersurface of its wings is what gives this species its name. Question Marks are a woodland species, and these butterflies rarely nectar at flowers. However, I have occasionally seen Question Marks taking nectar from butterfly bushes (buddleia), or in the case of the individual at left, a spring-blooming lilac.
This Question Mark butterfly was resting along the boardwalk at Cedar Bog. Question Marks fly from early spring to late fall, and they hibernate as adults through the winter. I have found them every month from March through November.
Questions Marks have different forms depending on the season. The individuals at left and above are the winter form. They have lighter-colored hindwings and a thin white (or pale blue) border along the edges of their wings. This beautiful winter-form Question Mark was photographed at Germantown MetroPark, October 9, 2016.