Red Helen vs Light Cahill Mayfly

Side-by-side species comparison

Attribute Red Helen Light Cahill Mayfly
Scientific Name Papilio helenus Heptagenia solitaria
Order Lepidoptera Ephemeroptera
Family Papilionidae Heptageniidae
Size 110-140 mm wingspan 9-13 mm
Habitat Forests Rivers & Streams
Diet Omnivores Omnivores
Regions Southeast Asia (Thailand, Vietnam, Malaysia, Indonesia, Myanmar, Cambodia, Laos) North America
Conservation Least Concern Least Concern

Red Helen

A large, elegant swallowtail butterfly with black wings marked by large creamy-white patches on the hindwings and red crescents along the hindwing margin. It has a slow, sailing flight.

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Did You Know?

The caterpillar has an osmeterium, a bright orange forked organ behind the head that releases a foul smell to deter predators.

Light Cahill Mayfly

A pale-colored mayfly highly prized by fly fishers for imitating hatches. Nymphs prefer moderate current over gravel substrates.

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Did You Know?

The Light Cahill dry fly pattern, designed to mimic this species, has been used since the 1880s.