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Spicebush Swallowtail

Papilio troilus[3]

The spicebush swallowtail is a black swallowtail butterfly whose green caterpillars carry big fake eyespots, looking like a tiny snake or tree frog; they feed on spicebush, sassafras and bays and are harmless.[1][2]

Group
Insect
Order
Lepidoptera
Family
Papilionidae
US records
30 states
Sources
3 cited
Updated
2026-10-15
Green spicebush swallowtail caterpillar showing large black-and-yellow eyespots
Green spicebush swallowtail caterpillar showing large black-and-yellow eyespots. (c) M. Whitson, some rights reserved (CC BY) — via iNaturalist, CC BY 4.0
On this page
  1. Identification
  2. Where it lives
  3. Biology
  4. Damage and signs
  5. Health risk
  6. Control
  7. Related profiles
  8. Common questions
  9. Sources

How to identify it

  • Older caterpillars are green with small blue spots and two pairs of large false eyespots; young caterpillars look like bird droppings.[1]
  • Caterpillars hide in a leaf folded over with silk when not feeding.[1][2]
  • The butterfly is black with tails on the hind wings, rows of pale spots along the edges and a blue to blue-green area on each hind wing; wingspan about 3.8 to 4.8 inches.[1][2]

Where it lives

Found throughout the eastern United States from southern Canada to southern Florida and west to Texas, less common west of the Mississippi River.[2]

US map: public records from 30 states since 1990 (GBIF).

Biology and life cycle

Eggs are laid singly under leaves; the chrysalis is green or brown (always brown in winter) and hangs from a twig by a silk band.[1][2]

Several generations occur each year.[1]

Damage and signs

  • Caterpillars feed on spicebush, sassafras, sweetbay, red bay, tulip tree and camphortree; leaf feeding is usually too minor to notice.[1][2]

Health risk

NC State calls the caterpillars harmless despite their eyespots.[1]

Control

Prevention

No control is needed; NC State advises against spraying.[1]

Common questions

What is the green caterpillar that looks like a snake?
Likely a spicebush swallowtail caterpillar, which has large fake eyespots.[1][2]
Is it poisonous?
No; NC State calls it harmless.[1]
Will it hurt my spicebush or sassafras?
Usually not; feeding is minor enough to go unnoticed.[1]

Sources

  1. NC State Extension, “Spicebush Swallowtail (PDIC Factsheet).” content.ces.ncsu.edu/spicebush-swallowtail (accessed 2026-10-15)
  2. University of Florida IFAS Extension (EDIS, Featured Creatures), “Spicebush Swallowtail, Papilio troilus (EENY-636/IN1107).” ask.ifas.ufl.edu/publication/IN1107 (accessed 2026-10-15)
  3. iNaturalist, “Papilio troilus taxon page (order and family).” www.inaturalist.org/taxa/58525 (accessed 2026-10-06)

Updated 2026-10-15. Built from sourced records. Spot an error? Tell us.