Gypsy moths aren't particularly large. Google gypsy moth images and you'll see a million. Did your moth have the same patterning as the male gypsy or does it look very different?

The largest moth you'll likely see in Michigan is likely the Cercropia, but Polyphemus, and Callosamia prothemea are also huge.

rhizo, I used to read your comments on another forum or forums over the years and I have wondered what happened to you. I am so glad you responded here. I read your other comments on this forum so realize you are well-versed in insects.

The forums I may remember you from and that I used to frequent are Hosta Forum, Cottage Garden Forum, Perennials Forum, Cactus & Succulents Forum, Container Gardening, House Plants, to name a few. I was "Patann" before Houzz took over GardenWeb.

Thank you SO MUCH for your comment above about the Cercropia, because this is a huge moth (still on my front door and it is 8 p.m. now) l and I cannot bear to kill it thinking it is a Gypsy. If it doesn't fy away tonight my husband says he will free it tomorrow morning. I saw a picture of its wing on a site but the name was not connected to it. I will try to link that site here if I can. If I can't, I will link it on a separate post on this Forum.

Thank you so much again.

Pat

rhizo, http://www.discoverlife.org/mp/20q?guide=Moth

See "8. Forewing shape" and within, see #434. That is about what his huge wing looks like.

I absolutely remember Patann!

I don't recognize that little wing section, unfortunately. Can your husband help with the photograph maybe?

Is the overall pattern mottled or are their eye spots on the wing? Any other special characteristics that stand out?

#434 wing segment similar to Lunate Zale, a medium-sized moth. The pattern would generally match the Black Witch Moth (Ascalapha odorata), that one is quite large.

Note that migration from south to Michigan can occur in June:

http://texasento.net/Map_BWM_Month.html