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Elm Sphinx Moth

Ceratomia amyntor

Summary 10

The Elm sphinx, (Ceratomia amyntor), sometimes called the Four-horned Sphinx, is a North American species of moth in the Sphingidae family. It has a wingspan of 3¼ - 4½ inches (8.2 - 11.5 cm). As the name suggests, the larvae (caterpillars) feed on elm trees (Ulmus), but they can also be found feeding on birch (Betula), basswood (Tilia), and cherry (Prunus). When the caterpillars are ready, they crawl to the bottom of the host tree, where they...

Egg 11

Tiny, translucent, lime-green eggs deposited on the underside of host leaves. The shells are transparent and pearly after hatching.

Imago 11

The overall coloring of the imago, or adult, Elm Sphinx is a gray-brown with wavy markings covering the forewings. In the upper center of the forewings, as with other Ceratomia species, there is a small white dot. The hindwings are a plain gray with a darker band running the length of the near-edge. The outer ends of the forewings and hindwings are both dashed with a light-dark-light pattern. Three broken, dark bands run the length of the body from the thorax to the tip of the abdomen. The antennae are stiff and wiry and have hook at the tips. Some specimens have a prominent splash of bright white on their upper head and wings and stand out considerably from other C. amyntor.

Larva 11

Larvae come in two different color phases; a green phase, and a dark phase which differs in shades of brown, orange, and somewhat of a pinkish brown. Larvae complete all five instars within approximately one month. The first instar is the same shade of green as its egg. As the larva progresses through its instars, change in structure is noticeable. The caterpillar sports four, long, horn-like projections- in addition to the tail horn- from above its head, which is why the Elm Sphinx is sometimes called the Four-horned Sphinx.

Life cycle 11

C amyntor adults fly as a single brood in the northern portions from June–July. There are two broods further south, flying later into the year, and five broods have been confirmed in Louisiana from March–October.

Tiny, translucent, lime-green eggs deposited on the underside of host leaves. The shells are transparent and pearly after hatching.

Larvae come in two different color phases; a green phase, and a dark phase which differs in shades of brown, orange, and somewhat of a pinkish brown. Larvae complete all five instars within approximately one month. The first instar is the same shade of green as its egg. As the larva progresses through its instars, change in structure is noticeable. The caterpillar sports four, long, horn-like projections- in addition to the tail horn- from above its head, which is why the Elm Sphinx is sometimes called the Four-horned Sphinx.

As with other Sphingidae, C. amyntor goes through a "wandering" phase where it stops feeding and burrows into the soil in order to pupate. Before pupating, the larva shrinks a considerable amount and then sheds its remaining skin that distinguishes it as a caterpillar, revealing its shell-like pupa.

The overall coloring of the imago, or adult, Elm Sphinx is a gray-brown with wavy markings covering the forewings. In the upper center of the forewings, as with other Ceratomia species, there is a small white dot. The hindwings are a plain gray with a darker band running the length of the near-edge. The outer ends of the forewings and hindwings are both dashed with a light-dark-light pattern. Three broken, dark bands run the length of the body from the thorax to the tip of the abdomen. The antennae are stiff and wiry and have hook at the tips. Some specimens have a prominent splash of bright white on their upper head and wings and stand out considerably from other C. amyntor.

Pupa 11

As with other Sphingidae, C. amyntor goes through a "wandering" phase where it stops feeding and burrows into the soil in order to pupate. Before pupating, the larva shrinks a considerable amount and then sheds its remaining skin that distinguishes it as a caterpillar, revealing its shell-like pupa.

Range 11

C. amyntor can be found from Nova Scotia west to Alberta and western North Dakota and Colorado; south to central Florida, the Gulf Coast, Texas, and New Mexico.

Habitat 12

Frequents hardwood woodland.

Life cycle 13

The adults are nocturnal and come to light. There is a single annual brood, which overwinter as pupae. Mature larvae are most often encountered after they wander from the host tree and seek a place with loose soil in which to pupate. The only Alberta record is for June 3, 2004.

Sources and Credits

  1. (c) Thomas Shahan, some rights reserved (CC BY-NC-ND), https://www.flickr.com/photos/opoterser/12938069144/
  2. (c) Kevin Ripka, some rights reserved (CC BY), https://www.flickr.com/photos/zooeyripka/6003941468/
  3. (c) Lee Elliott, some rights reserved (CC BY-NC-SA), https://www.flickr.com/photos/lfelliott/16243682271/
  4. (c) Ilona L, some rights reserved (CC BY-NC-SA), https://www.flickr.com/photos/14379121@N03/14553291835/
  5. (c) Jenn Forman Orth, some rights reserved (CC BY-NC-SA), https://www.flickr.com/photos/urtica/9332768568/
  6. (c) Jim Vargo, some rights reserved (CC BY-NC-SA), http://mothphotographersgroup.msstate.edu/Files1/JV/300/JV7786-100.jpg
  7. (c) Kenzi, some rights reserved (CC BY-NC), uploaded by Kenzi
  8. (c) Esteban Muldavin, some rights reserved (CC BY-NC), uploaded by Esteban Muldavin
  9. (c) Robert J. "Bob" Nuelle, Jr. AICEZS, some rights reserved (CC BY-NC), uploaded by Robert J. "Bob" Nuelle, Jr. AICEZS
  10. Adapted by Allie Hay from a work by (c) Wikipedia, some rights reserved (CC BY-SA), http://en.wikipedia.org/wiki/Ceratomia_amyntor
  11. (c) Wikipedia, some rights reserved (CC BY-SA), http://en.wikipedia.org/wiki/Ceratomia_amyntor
  12. (c) University of Alberta Museums, some rights reserved (CC BY-NC), http://eol.org/data_objects/31891548
  13. (c) University of Alberta Museums, some rights reserved (CC BY-NC), http://eol.org/data_objects/31891549

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(c) Discover Life and original sources, some rights reserved (CC-BY-NC-SA)

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