Prismatocerus plagiatus (Germar, 1838)
Original description (Homoeocerus plagiatus) in:
Germar, C. F. 1838. Hemiptera Heteroptera Promontorii bonae spei nundum descripta, quae collegit C. F. Drege et proponit C. F. Germar. Revue Entomologique (Silbermann) 5:147-148.
https://www.biodiversitylibrary.org/item/82337#page/149/mode/1up
The thorax is muted, greyish-testaceous, the head and thorax above are brown, the antennae are red-variegated, the longitudinal stripes of the elytra are black. [...]
Redescription (Prismatocerus plagiatus) in:
Stål. 1866. Hemiptera Africana 2:66, 67
https://www.biodiversitylibrary.org/item/35344#page/340/mode/1up
Translated from Latin:
Dark-cinnamon, pubescent, underneath paler, brownish-punctate; Abdominal margin pale, thinly
punctuated, blood-red above, with a narrow ribbon on both sides, and with black apical segments; the first and fourth joints of the antennae are dark brown, the second and third are yellow-rusty, with a black tip, and the third tip is distinctly expanded; the hemelytra are yellow-cinnamon, with a dense brown-pointed clavus, corium decorated with an irregular black stripe of leather near the costal margin; membrane dark brown, Hindwings infustcated.
Length 15 - 17 mm, width 4 - 5.5 mm.
Photo of Philonus nigrovittatus Stål, 1855 (synonym).
http://www2.nrm.se/en/het_nrm/n/homoeocerus_nigrovittatus.html
References:
http://coreoidea.speciesfile.org/Common/basic/Taxa.aspx?TaxonNameID=1188882
iNat observations:
https://www.inaturalist.org/observations/190281939
https://www.inaturalist.org/observations/144846640