Seothyra semicoccinea is a species of spider in the family Eresidae. It is endemic to the Eastern Cape province of South Africa.
Seothyra semicoccinea is endemic to South Africa, known only from the type locality of Willowmore in the Eastern Cape.
The species is a ground-dweller that has been sampled from the Nama Karoo biome at an altitude of 815 m above sea level.
The species constructs retreat-webs. Males wander in search of mates.
Seothyra semicoccinea is known only from the male.
Seothyra semicoccinea is listed as Data Deficient for taxonomic reasons. The species has a very restricted distribution. More sampling is needed to collect the female and to determine the species' range.
The species was originally described by Eugène Simon in 1906. It was revised by Dippenaar-Schoeman in 1991.