Hemirrhagus is a genus of Mexican tarantulas that was first described by Eugène Louis Simon in 1903. It is considered a senior synonym of Spelopelma. Species of the genus Hemirrhagus are 5 to 12 cm long, usually black in colour, the urticating hairs on the opisthosoma are arranged in one dorsomedian patch, two dorsal paramedian patches, or two lateral patches. It is unique amongst the theraphosine genera because of the retrolateral coxal heels, the shape of the male palpal bulb, and the urticating hairs on the abdomen are reduced or completely missing. It is the only genus with epigean, troglophile and troglobitic species.

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