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Euclea delphinii
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Arthropoda
Class:	Insecta
Order:	Lepidoptera
Family:	Limacodidae
Genus:	Euclea
Species:	E. delphinii
Binomial name
Euclea delphinii (Gray, 1832)

The spiny oak slug (Euclea delphinii) is the larval form (caterpillar) of a moth in the family Limacodidae.

There is one generation a year in most of the northern parts of its range, with caterpillars seen from late June to October (Wagner 2005). Two generations or more from Missouri south.

Eggs are laid singly or in small clusters on leaves (Wagner 2005).

The larva is flattened and ovoid in outline, with spiny tubercules along the back and sides. These are venomous, producing symptoms in humans that vary from mild itching and burning to more serious reactions that require medical attention (Florida Poison Information Center 2015). The sides have craters ringed with black or white along them. In the final instar they usually have two to four sets of black hairs at the tail end, that can fall off, called 'caltrop' spines after the Roman defensive weapons. Colourful, but the colours vary enormously (Wagner 2005). Like all limacodids, the legs are shortened and the prolegs are reduced to suction cups. Maximum length, 20 mm (Wagner 2005).

Pupates in a cup-shaped cocoon with a circular escape hatch.

The small (1 cm) moth is 'hairy' and brown, with green patches on the upper wing. The underwing is a paler grey-brown.

A number of parasitoids have been recorded on spiny oak slug caterpillars, including tachinid flies (Uramya pristis; Austrophorocera einaris; Compsilura concinnata), eulophid wasps (Platyplectrus americana; Pediobius crassicornis), and braconid wasps (Cotesia empretiae; Triraphis discoideus). An egg parasitoid of genus Trichogramma was also recorded.(Gates et al 2012)

Eats a variety of deciduous trees and shrubs, not limited to: apple, ash, basswood, beech, birch, blueberry, cherry, chestnut, hackberry, hickory, maple, oak, poplar, sycamore and willow (Wagner 2005).

• "Stinging Caterpillars". Florida Poison Information Center – Tampa. 2015. Retrieved 2018-08-25.
• Wagner, DL (2005). Caterpillars of Eastern North America. Princeton University Press.
• Gates, Michael W.; Lill, John T.; Kula, Robert R.; O'Hara, James E.; Wahl, David B.; Smith, David R.; Whitfield, James B.; Murphy, Shannon M.; Stoepler, Teresa M. (January 2012). "Review of Parasitoid Wasps and Flies (Hymenoptera, Diptera) Associated with Limacodidae (Lepidoptera) in North America, with a Key to Genera". Proceedings of the Entomological Society of Washington. 114 (1): 24–110. doi:10.4289/0013-8797.114.1.24.

• Adult @ Maryland moths
• BugGuide images of adults and larval variations