Montana Field Guide

The One-eyed Sphinx Moth (Smerinthus cerisyi) is a large (62 - 90 mm wingspan) heavy-bodied sphinx moth. The forewings are pale grey (occasionally tan) with a rather complex pattern of darker grey and black banding. The median and terminal areas in particular are dark. The outer margin of the forewing is scalloped, with a "tooth" at the anal angle. The hindwings are bright rose-pink, shading into tan toward the margin. There is a large black spot in the anal angle containing a bright blue circle, often incomplete and sometimes with a second blue crescent above. The thorax is black, contrasting sharply with the broad pale grey tegulae (Anweiler and Robinson no date).

Shropshire and Tallamy (2025) provide a list, with synonymies, of 13,055 described native, exotic, and occasional straying Lepidoptera species of North America, north of Mexico; known but undescribed taxa, taxa with unresolved taxonomy, and excluded species are also included. The main manuscript includes links to supplementary materials, including a reference list for Lepidoptera of North America north of Mexico, and a filterable spreadsheet with information on taxonomy, synonymy, size ranges of species, distribution by state, province, and country with references, and host-plant Family and Genus associations with references.

The adults are nocturnal and come to lights. The larvae are solitary defoliators. There is one flight from May-August. The long flight period may indicate that there is more than one generation per year in Alberta (Anweiler and Robinson no date).

The very similar Twin-spotted Sphinx Moth (S. jamaicensis) has two blue bars instead of a blue circle in the hindwing spot, and the pink is sharply divided from the tan outer part of the hindwing. Pectinations on the male antennae are also much shorter in cerisyi than in S. jamaicensis (Anweiler and Robinson no date).

Valleys and streamsides (Opler et al. 2010).

Shropshire and Tallamy (2025) provide a link to a supplemental filterable spreadsheet with information on host-plant Family and Genus associations with references for all Lepidoptera species of North America, north of Mexico.

The larvae feed on willow (Salix) and poplar (Populus). The adults do not feed (Opler et al. 2010).