NC State Extension Publications

Description and Biology

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The tersa sphinx moth, Xylophanes tersa, is a fairly large moth with a wingspan of 23/8 to 31/8 inches. The forewings are grayish brown with a pale line that extends to the tip. The pale line is set off by darker lines on each side. The hind wings have large black patches with contrasting pale spots. The abdomen is brown to cinnamon with barely contrasting lines along the back and a paler line along the side. At sunset, moths begin drinking nectar from flowers. Females release a pheromone that calls males from a considerable distance. Males come to lights, but females are seldom taken in that way. Tersa sphinx caterpillars are called "sphinxes" because they can rear up slightly and retract the head and three thoracic segments into the abdomen, a posture that somewhat resembles a sphinx. These caterpillars are snake mimics with a realistic pair of light-ringed eyespots on the first abdominal segment. Tersa sphinx caterpillars are variable in appearance. Some are pale green with pale eye spots whereas others may be dark with vivid eyespots. All specimens have a noticeable "horn" at the rear. These caterpillars grow to about 3 inches long. When mature, tersa sphinx caterpillars crawl to the soil surface and burrow into plant debris to molt into a pupa. The pupa is tan with eye spots down the abdomen. We have two or more generations per year in North Carolina.

Tersa sphinx moths are active after sunset.

Tersa sphinx moths are active after sunset.

Tersa sphinx caterpillar

Tersa sphinx caterpillars grow to three inches long.

Some tersa sphinx caterpillars are pale green

Some tersa sphinx caterpillars are pale green.

Tersa sphinx caterpillars presumably gain protection from predat

Tersa sphinx caterpillars presumably gain protection from predators by mimicing snakes.

Tersa sphinx pupa

Tersa sphinx pupae are usually under leaf litter.

Host Plants

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Tersa sphinx moths visit Chinese violet, common milkweed, four o' clocks, honeysuckle, and even prairie white fringed orchid for nectar. Their caterpillars feed on pentas as well as broadleaf buttonweed, candy corn vine, catalpa, firebush, and smooth buttonplant. They have also been reported from joe-pie weed.

Residential Recommendations

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In spite of the threatening appearance of horn at the rear of tersa sphinx caterpillars, these insects are harmless and can be plucked from their host plants and trampled under foot. In the rare case that there are too many caterpillars for manual control, any insecticide labeled for landscape use should give more than adequate control.


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For assistance with a specific problem, contact your local Cooperative Extension Center.

This Factsheet has not been peer reviewed.


Professor Emeritus
Entomology and Plant Pathology

Find more information at the following NC State Extension websites:

Publication date: Sept. 13, 2017
Revised: June 22, 2022

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