Information and photos by Kyle Johnson
(Edited by Marcie O’Connor)

Here are some specimen images of Lithophane disposita vs. the undescribed “near disposita“.

True disposita averages darker gray (with more brown cast in overwintered individuals) and differs in details of the wing pattern, esp. in the median area (see red highlights in second image). True disposita is a more northern species associated with wetlands and other habitats with willows.

“Near disposita” is more southerly and associated with drier often hilly deciduous woodlands.

It is rare to get both at the same site in Wisconsin; for the most part “near disposita” occupies the Driftless area of western WI, with true disposita occupying the rest of the state (but it also occurs very locally in the Driftless area).

(Click once on the photos to see them slightly enlarged.  Click twice to see them full size.)

Here the main differences in markings are outlined in red.  The gap is narrow in disposita, wider in ‘near disposita‘.

This difference is one helpful character, but is not diagnostic by itself.  The two species look different when they’re side by side, but as with many species, the differences are not always easy to describe in words.