Caterpillars
Images and information on the biology of caterpillars in the Costa Rican and Ecuadorian regions.
http://www.tulane.edu/~ldyer/lsacat/

Caterpillars of Eastern Forests
Includes species descriptions, life cycle and morphology information, and tips on photographing, rearing, collecting, and preserving specimens of many caterpillars occurring in forests of the eastern United States
http://www.npwrc.usgs.gov/resource/insects/cateast/cateast.htm

Caterpillars of the Pacific Northwest
A field guide to caterpillars commonly found in forests and woodlands of the Pacific Northwest, including sections describing the natural history, nomenclature, identification keys, and details for collection and preservation of specimens
http://www.npwrc.usgs.gov/resource/insects/catnw/catnw.htm

Pipevine Swallowtail
Photos of adult of this species and caterpillars in various stages.
http://www.carolinabutterflysociety.org/baldwin/pipevine01.htm

Butterfly and Moth Lifecycles
Photographs of captive moths and butterflies, including cocoons and caterpillars, mostly from Nebraska, USA.
http://cse.unl.edu/~scotth/moths-butterflies.html

Black Swallowtail Caterpillar: Papilio polyxenes
Photographs of these handsome caterpillars and information on the natural history of the species.
http://entomology.uark.edu/museum/blswcat.html

Ailanthus Webworm Moth: Atteva punctella
Photographs of adults and caterpillars and information on the natural history of this species.
http://entomology.uark.edu/museum/ailamoth.html

Stinging Rose Caterpillar: Parasa indetermina
Photographs of adults and caterpillars and information on the natural history of this moth.
http://entomology.uark.edu/museum/stinrose.html

Spodoptera ornithogalli: Yellow-striped Armyworm
Photographs of this moth and its caterpillars, with information on its symptoms, life cycle and description.
http://www.ento.okstate.edu/ddd/insects/yellowstripedarmyworm.htm

Plodia interpunctella: Indian Meal Moth
Photographs of adults and caterpillars and information on the natural history of this household pest.
http://entomology.uark.edu/museum/indian.html