Horse Stomach Bot Fly vs White Miller Mayfly

Side-by-side species comparison

Attribute Horse Stomach Bot Fly White Miller Mayfly
Scientific Name Gasterophilus intestinalis Ephoron virgo
Order Diptera Ephemeroptera
Family Oestridae Polymitarcyidae
Size 12-16 mm 12-18 mm
Habitat Farmland Rivers & Streams
Diet Omnivores Omnivores
Regions Cosmopolitan wherever horses are kept Europe, Western Asia
Conservation Least Concern Least Concern

Horse Stomach Bot Fly

A bee-like fly that glues eggs to horse leg hairs where they are ingested during grooming. Larvae attach to the stomach lining and develop for months before passing out.

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Did You Know?

Larvae survive the acidic horse stomach by secreting a protective alkaline buffer around themselves.

White Miller Mayfly

A white-bodied European mayfly that emerges in enormous synchronized swarms at dusk. Females are unique among mayflies in that they moult directly into the spinner stage.

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Did You Know?

Swarms at bridges and streetlights can be so thick they cause traffic hazards.