Hemaris thysbe, the Hummingbird Clearwing Moth or Common Clearwing (wingspan 38-50 mm), readily visits flowers by day throughout the eastern half of the U.S. and Canada, where it ranges far to the north, even into the Yukon. It is not difficult to see why many gardeners would mistake an Hemaris thysbe moth for a small hummingbird as it hovers, sipping nectar from flowers through a long feeding tube. The moth hovers briefly, sipping for only a few seconds before darting off to a new flower. Green body "fur" and burgundy wing scales suggest a small ruby throated hummingbird.

Adult sphinx moths are medium to large moths with wingspans ranging from about 1.25 inches to 4.75 inches. The snowberry clearwing is one of the smallest moths in this group, while the five-spotted hawk moth is one of the largest. Its larva is the familiar tomato hornworm. The Carolina sphinx, whose larva is known as the tobacco hornworm, weighs only one to two grams, but it flaps its wings an astonishing 25 to 30 beats per second. Some sphinx moths have been clocked at speeds as high as 30 mph.

Sphinx moths are often mistaken for hummingbirds and bumblebees because of their similarities in size, foraging behavior and feeding structures. Many sphinx moths are nocturnal, but several species are diurnal, meaning they are active during the daytime when hummingbirds and bumblebees are also foraging. Adult sphinx moths have a long, straw-like "tongue," called the proboscis, which they keep curled under the head. They use it to suck nectar from the flower. The nectar is rich in sugar, which fuels the energy required for hovering. Hummingbirds also have a long tongue to lap up nectar.