Having never seen a Humingbird, my husband and I thought that might be what were seeing an evening last week. After a very fun, multi-lens, photography session, he and I researched and realized we had a couple (at least) of White-Lined Sphinx Hummingbird Moths. We had a blast capturing these resourceful fellows. In the four summers we have lived in Western Iowa, we have never seen these before...must be all the rain!
Family: Sphinx Moths, Hawkmoths (Sphingidae)
Subfamily: Macroglossinae (Macroglossinae)