Liorhyssus hyalinus is a species of scentless plant bugs belonging to the family Rhopalidae, subfamily Rhopalinae. Length is about 7 mm. As the whole Rhopalidae family, it is a plant feeder. It mainly feeds on Compositae and Erodium species. This species can be distinguished by the length of the hyaline membrane of the hemelytra, which extends beyond the black upperside of the abdomen. It is found in most of Europe.