In Southern and Appalachian speech, a devil horse (or "devil’s horse") is a folk name for either a praying mantis or, in some areas, a large black horsefly - tied to old beliefs about danger or evil insects.
★ "Devil horse" is another Southern insect myth name, like "snake doctor" and "devil’s darning needle." It blends superstition with everyday encounters on porches, barns, and pastures. ★
Origin and Etymology
Documented in Southern and Appalachian folklore since the late 19th and early 20th centuries. The praying mantis was often called a "devil horse" because of its odd stance and piercing forelegs. In coastal and swampy regions, "devil horse" also referred to the giant black horsefly (Tabanus atratus) because of its painful bite.
Usage Notes
Devil horse - primary folk name for a praying mantis in the South/Appalachia.
Secondary usage for the large black horsefly, especially in coastal or lowland areas.
Common myths: it can spit tobacco juice in your eye; it can kill a horse; it’s poisonous - none are true.
Created by The Hillbilly Dude, this site is a growing field guide to culture, speech, memory, and meaning - rooted in Appalachia but reaching across the world. Every slang word, saying, accent and story is gathered from first-hand experience and trusted sources. The goal: preserve authentic voices and share them with writers, learners, and culture lovers everywhere - with a little humor thrown in here and there. Read more...
Gimme a choice between a 'devil horse' or a 'deviled egg,' I'm choosin' the horse one any day of the week. 
