It is grayish brown in color with black bands across the top margins of the hindwings and five orange spots along each side of the abdomen. The large caterpillars occur in two color morphs, bright green or gray with scattered white speckles throughout the back and a horizontal white stripe on the side margin of each segment. It was most common historically on Maui. However, many of the host plants recorded for the species are not native to the Hawaiian Islands, and include tree tobacco, commercial tobacco, and tomato plants. Adult moths can be found year round but seem to be most active during two periods, January to April and September to November.
Adult moths are strong fliers.
Additional small isolated populations are now known from other parts of Maui. The native host plant is found in endangered ecosystems, dry and mesic forests, and has been adversely affected by feral animals, alien plant invasions, and habitat conversions associated with development. A high percentage of the eggs of the sphinx moth are destroyed by alien parasitoid wasps and ants. In addition, the moth is also susceptible to overcollection by individuals for their personal collections or for trade. Because the remaining populations are small and restricted, the potential for extinction from a chance event, such a fire or a hurricane, is greatly increased.