Like other sphinx moths, adult snowberry clearwings have protruding heads, large eyes, a large, furry thorax, and a conical abdomen that extends well beyond the hindwings when the moth flies. This sphinx moth mimics a bumblebee: The body is fuzzy golden yellow, and the abdomen has black and yellow bands. Seen from the side, the head has a black band that passes through the eye and continues along the side of the thorax. The wings have large central patches that lack scales and are thus clear. The dark scales on the wings are black, and the dark band on the outer margin of the wings is relatively narrow. The legs and most of the underside of the body are black.
Larvae are usually green with black spots around the spiracles. Behind the head is a yellow “collar.” As with other sphinx moths, the caterpillar is a “hornworm” with a pointy “tail” arising from the end of the body; the horn on this species is black with a yellow base.
Similar species: The hummingbird clearwing (H. thysbe) is another sphinx with clear wings and a fuzzy, beelike body. It is slightly larger than the snowberry clearwing, and it has whitish legs and white under the body. The dark scales on the wings are brown (not black). The boundary between the clear area and outer dark area is ragged (not smooth). Also, it has a dark, diagonal area at the base of the forewing that the snowberry lacks.
The slender clearwing (H. gracilis) occurs only locally; uncommon in Missouri, it is more common to the north and on the east coast. It always has brown or rust-colored bands on the side of the thorax, beneath where the wings attach. Also, the legs are reddish (not black, not white).
Bumble bees: Clearwing moths can be quickly distinguished by their hummingbird-like flight. These moths usually do not alight and walk on flowers the way bees do.