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Wavy-lined Emerald

Synchlora aerata[4]

The wavy-lined emerald is a small green moth of fields, prairies and roadsides. Its caterpillar, the camouflaged looper, is an inchworm that covers itself with clippings of flower petals and other plant bits, so it either blends into the flower it is eating or passes for a crumb of debris.[1][3]

Group
Insect
Order
Lepidoptera
Family
Geometridae
US records
45 states
Sources
4 cited
Updated
2026-11-09
Wavy-lined emerald moth with its pale green wings spread flat, crossed by wavy white lines, and a white stripe along its abdomen
Wavy-lined emerald moth with its pale green wings spread flat, crossed by wavy white lines, and a white stripe along its abdomen. (c) Bill Keim, some rights reserved (CC BY) — via iNaturalist, CC BY 4.0
On this page
  1. Identification
  2. Look-alikes
  3. Where it lives
  4. Biology
  5. Damage and signs
  6. Health risk
  7. Control
  8. Related profiles
  9. Common questions
  10. Sources

How to identify it

  • Like most emeralds, it is a green moth that rests with its wide wings spread out to the sides. Look for mildly wavy white lines across the wings, a pale green fringe along the wing edges, and a long, thin white stripe running the whole length of the abdomen.[1]
  • The wingspan is only 1/2 to 1 inch.[1]
  • The caterpillar is an inchworm decorated with petal fragments and other plant bits, which it binds with silk to pale projections along its back. Under the costume the body is mottled brown, black and white and densely set with tiny spines, with an oblique white line through each breathing pore.[3]
  • Fresh petal clippings can make the caterpillar pink, purple or golden yellow; as they dry, they look like crumbs.[1]
  • A full-grown caterpillar is about 1.5 cm (a little over 1/2 inch) long.[3]

Look-alikes

Look-alikeHow to tell them apart
Southern emeraldA close relative with similar coloring, but its cross lines are much more scalloped or jagged, forming little points where they cross the wing veins. It is more numerous in the southeastern United States.[1]
Red-fringed emeraldRed-fringed emeralds have a reddish fringe on the wing edges and white spots on the abdomen that are usually outlined in red. The wavy-lined emerald's fringe is pale green, and its abdomen has an unbroken white stripe.[2]

Where it lives

In its guide to eastern forest caterpillars, the USDA Forest Service gives its range as southern Canada to Florida and Texas, in fields and other open habitats. In Missouri it is found statewide and is most abundant in and near prairies, pastures, old fields and roadsides.[3][1]

US map: public records from 45 states since 1990 (GBIF).

Biology and life cycle

The caterpillars feed on many plants. They are most often seen on composite flowers such as sunflowers, coreopsis, coneflowers, blazing stars, goldenrods, asters, black-eyed Susans, yarrow, ageratum, boneset and daisies, and they also use blackberry, raspberry, rose, sage, St. John's-wort and other plants.[1][3]

The costume changes with the menu: the caterpillar trims fragments from each new flower it moves to, and because its covering usually includes fresh stamens and petals, it apparently adds new material daily.[3]

Missouri has two or three broods a year. In Connecticut and Maryland there are two generations, with full-grown caterpillars from April into June and again from July into September; northern New England has one.[1][3]

It spends the winter as a partly grown caterpillar, about half developed.[1][3]

Damage and signs

  • The caterpillars feed on flowers and foliage, including sunflower-family garden flowers and blackberries. Neither source describes the feeding as a problem for gardens.[1][3]

Health risk

Neither the Missouri Department of Conservation nor the USDA Forest Service mentions any bite, sting or other risk to people.[1][3]

Control

Prevention

Neither source recommends any control. The Missouri Department of Conservation treats finding one of the decorated caterpillars as a special treat and notes that insects like this moth are important food for birds and other predators.[1][3]

Common questions

What is the little inchworm covered in flower petals?
It is a camouflaged looper, the caterpillar of the wavy-lined emerald moth. It snips pieces of petals and other plant bits and attaches them to its back with silk.[1][3]
Where can I find camouflaged loopers?
Scan the flower heads of sunflowers, asters, goldenrods, coneflowers and other composites for something that looks out of place, such as a clump of debris that starts to walk like an inchworm.[3][1]
Do camouflaged loopers hurt flowers?
They do eat flowers and foliage, but neither the Missouri Department of Conservation nor the USDA Forest Service treats them as pests or recommends control.[1][3]

Sources

  1. Missouri Department of Conservation, “Wavy-Lined Emerald (Field Guide).” mdc.mo.gov/discover-nature/field-guide/wavy-lined-emerald (accessed 2026-11-09)
  2. Missouri Department of Conservation, “Red-Fringed Emerald (Field Guide).” mdc.mo.gov/discover-nature/field-guide/red-fringed-emerald (accessed 2026-11-09)
  3. USDA Forest Service, Forest Health Technology Enterprise Team, “Geometroid Caterpillars of Northeastern and Appalachian Forests, FHTET-2001-10 (D. L. Wagner, D. C. Ferguson, T. L. McCabe and R. C. Reardon, September 2001; scanned copy).” archive.org/details/geometroidcaterp00wagn (accessed 2026-11-09)
  4. iNaturalist, “Synchlora aerata taxon page (order and family).” www.inaturalist.org/taxa/126204 (accessed 2026-11-09)

Updated 2026-11-09. Built from sourced records. Spot an error? Tell us.