March Brown Mayfly vs Neotropical Blue Hairstreak

Side-by-side species comparison

Attribute March Brown Mayfly Neotropical Blue Hairstreak
Scientific Name Rhithrogena germanica Pseudolycaena marsyas
Order Ephemeroptera Lepidoptera
Family Heptageniidae Lycaenidae
Size 10-14 mm 35-45 mm wingspan
Habitat Rivers & Streams Rivers & Streams
Diet Omnivores Nectar Feeders
Regions Europe Brazil, Peru, Colombia, Ecuador, Bolivia
Conservation Near Threatened Least Concern

March Brown Mayfly

A spring-emerging mayfly with a brownish body and two tails, historically important to European fly fishing. Its flat nymphs cling to rocks in fast water.

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Did You Know?

This species has declined significantly in many European rivers due to pollution and is now considered an indicator of water quality.

Neotropical Blue Hairstreak

A brilliant iridescent blue hairstreak butterfly with delicate tail streamers on the hind wings. Its underside is pale grey with fine dark lines.

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Did You Know?

Its false head pattern on the hind wing tips, complete with fake antennae, tricks predators into attacking the wrong end.