Ischnorhynchus ericae Horváth, 1908b: 561. New name for geminatus Fieber, 1861.
Ischnorhynchus geminatus Fieber, 1861a: 200 (junior secondary homonym of Lygaeus geminatus Say, 1832). STS: male, female, Europe, middle and south; lost.
Ischnorhynchus resedae (non Panzer, 1797): Douglas & Scott, 1865: 233. Misidentification (see J.A. Slater, 1964a: 370).
Ischnorhynchus geminatus var. grisescens Puton in Noualhier, 1889: 295 (syn. or downgraded to subspecies by Péricart, 1999a: 238, suspected). LT (Péricart, 1999a: 238): Canary Islands, female, Tenerife; MNHN.
Ischnorhynchus truncatulus var. horvathiana Kirkaldy, 1909b: 31. New name for geminatus Fieber, 1861.
Kleidocerys franciscanus (non Stål, 1860, partly): Barber, 1953: 277. Misidentification (see J. A. Slater, 1964a: 372).