North American caterpillars

2057 Garden Tiger (Arctia caja) caterpillar - fully grown © Steve OgdenThis North American caterpillar gallery has been added in response to the large number of caterpillar identification enquiries being received from US states and Canada.

The photos and sightings received will hopefully help others identify the most common caterpillars.

Caterpillars and larvae are terms used for the larval stage of an insect.

Please note that there are some hairy caterpillars found in many American states and Canada with hairs that can cause allergic skin reactions. Stinging caterpillars of North America

Io moth caterpillar (Automeris io) recorded in Spring, Texas USA photo Kathryn Sword

Identifying a caterpillar

To simplify finding a caterpillar in the galleries species are broken into more commonly described terms and do not follow the scientific names and families.

Large caterpillars of North America

Hairy caterpillars of North America

Stinging caterpillars of North America

Loopers, Inchworms and Spanworms of North America

Butterfly caterpillars of North America

Other insect caterpillars/larvae of North America

2026 The Vapourer Moth (Orgyia antiqua) caterpillar - brown tufted form © Steve Ogden

Identification of American caterpillars

When identifying caterpillars the following pointers may be helpful.

Many caterpillars radically change appearance as they grow and moult (change skins).

Counting the legs may help by placing the caterpillar in a certain order or family of insects.

Some caterpillars found in the United States may also occur in other parts of the world and although the English species name may differ the scientific latin name will be the same. An example being Orgyia antigua which is better known as the Rusty Tussock Moth in the US but called The Vapourer moth in the UK.

So when identifying a caterpillar it may also help to look at the British caterpillar gallery which also includes some species occurring in other countries and continents of the world.

Please note

There is still much to learn about the early stages of many moths and butterflies. Whilst every effort is made to provide accurate identifications and information errors could occur. Should an error be spotted please let us know.

American caterpillar pests

Eastern Tent caterpillars in Idaho, USA on silk web photo © Amanda Fingerson

Several species of caterpillars are pests of trees and crops. These include several species known as Cutworms that feed low down among the roots and lower foliage of crops.

A few species can also be a danger to health including some of the Hairy caterpillars and stinging slug caterpillars

The caterpillars or larvae of other insects such as beetles and sawfly are also major pests of many agricultural crops and garden shrubs.

This photo of Eastern Tent caterpillars was taken by Amanda Fingerson in the state of Idaho.

More are featured in the Hairy Caterpillar gallery

American hairy caterpillars

White Marked Tussock moth caterpillar in LA, USA photo © Lynn Norwood

The Hairy caterpillars of North America gallery contains both hairy caterpillars form several different moth families.

Also included are several species of commonly sighted Tussock Moth caterpillars which often have extraordinary tufts and long lashes of hair.

The White Marked Tussock Moth featured was photographed by Lynn Norwood in Los Angeles, California.

American stinging caterpillars

Stinging Saddleback caterpillar Acharia stimulea,North Carolina, USA © 2015 Shawn WilliamsThe extraordinary looking Saddleback caterpillar, Archaria stimulea, is a common species in much of North America.

It’s a member of the Limacodidae family of moths which are best known for the stinging hairs of their caterpillars.

Every year there are many reports of Saddleback caterpillars, also referred to as slug caterpillars, stinging people in many states.

It is one of the most frequently enquired about caterpillars and the one shown left was recorded by Shawn Williams in North Carolina.

Skin contact with these caterpillars should be avoided.

Stinging caterpillars of North America

Large American butterfly caterpillar

Giant Swallowtail butterfly caterpillar, Texas, USA © L.WilderFortunately most caterpillars are harmless and play a vitally important part in our ecosystem.

Many pupate and emerge as beautiful butterflies and moths to be enjoyed and appreciated by all.

This photo of the caterpillar of the beautiful Giant Swallowtail butterfly was sent in by Laura Wilder taken on a Citrus Tree in her garden on the Gulf Coast of Texas, USA.

These beautiful butterflies have caterpillars that resemble bird droppings to avoid detection by predators.

Butterfly caterpillars of North America

Largest caterpillar in the United States

Regal Moth caterpillar (Citheronia regalis) searching for place to pupate in the soil, New Jersey, USA © J.PaceMany caterpillars are less than 2 inches long but some are much longer.

This Regal Moth caterpillar is one of the largest caterpillars found in North America reaching almost 6 inches in length and was recorded by Johnathan Pace in the state of New Jersey.

Many of the large caterpillars commonly found in the US are members of the Hawk-moth family Sphingidae

Caterpillars in this family are found all over the world and often easily identified by their tail spikes.

Some of these are featured in Large caterpillars of North America

White fluffy caterpillars

Butternut Woollyworm found feeding on Hickory in Idaho, USA - photo © Jill GambonSome caterpillars in the United States look so extraordinary that it’s not always immediately obvious they are actually caterpillars.

Often the first task is deciding which order of insects such as butterfly or moth (Lepidoptera), fly (Diptera) or beetle
(Coleoptera) a caterpillar belongs to.

This photo of the extraordinary Butternut Woolly Worm, the caterpillar of the sawfly Eriocampa juglandis, was received from Gill Gambon, taken in her garden in Rockland, in the state of Massachusetts.

Other sawfly and insect larvae can be seen in the Other insects caterpillars of North America

These are just a sample of your enquiries. Many more of your images will be added to the gallery with accreditation and those of particular interest included in a ‘latest sightings’ news item – so please keep sending them in to Steve Ogden – email address –

Please note: even if the caterpillar is not immediately identified the photo can still be added to the gallery for others to identify.

Caterpillar galleries

Large caterpillars of North America

Hairy caterpillars of North America

Stinging caterpillars of North America

Loopers, Inchworms and Spanworms of North America

Noctuid caterpillars of North America

Butterfly caterpillars of North America

Other insects caterpillars of North America