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Modest Sphinx Moth (Pachysphinx modesta)

The modest sphinx moth is a member of the family of hawk moths, first described in 1839 by American entomologist Thaddeus William Harris.

Modest Sphinx Moth


Scientific Classification

  • Family: Sphingidae
  • Genus: Pachysphinx
  • Scientific Name: Pachysphinx modesta

Description and Identification


The larva is green and covered with white spots. Unlike other caterpillars, its head is pinkish-purple and shaped like a flat teardrop. There are 3-6 yellow diagonal lines throughout its body and a white diagonal line that merges with the white horn sticking out from their posterior end.


The pupation phase takes place in the burrows, underground.

Modest Sphinx Moth Pupa


Adult Moth

Sexual Dimorphism: Present but not prominent.

Color and Appearance

Forewing: When the wings are opened, it is observed that the upperside is gray, with the basal and outer regions being lighter than the median. When the wings are closed, the colors remain visible.

Hindwing: When the wings are opened, it is gray with a crimson spot and a blue triangle-like pattern near the outer margin. When the wings are closed, the crimson and blue regions cannot be seen.

Average wingspan: 7.6 – 12 cm

Flight pattern: Erratic

Season: May to September

pachysphinx modesta



Eggs are laid on the host plants, hatching in about 9 days.

Quick Facts

Other namesPoplar Sphinx moth
DistributionFrom Canada to the southern United States
HabitatMoist mountainlands, also creeks, river banks, and streams
Lifespan of Adults10-30 days
Host PlantsAspen, cottonweed, poplar, and willow
Adult DietDoes not feed

Did You Know

Modest Sphinx Moth Image


Poplar Sphinx Moth


Modest Sphinx Moth Picture


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