Bibio incrassatus Heer, 1849: 221 Revision of fossil Bibionidae (Insecta: Diptera) from the Miocene of Radoboj, Croatia Skartveit, John Krizmanić, Katarina Zootaxa 2020 2020-04-03 4759 3 351 378 929RQ Heer, 1849: 221 Heer 221 1849 [151,545,1556,1583] Insecta Bibionidae Bibio Animalia Diptera 18 369 Arthropoda species incrassatus  XVI Fig. 12) but it is difficult to tell what it is. Heer’s figure may suggest the presence of a vein R 2+3and a vertical crossvein R-M, in which case the species should be placed in the genus  Plecia, possibly as a synonym of  Plecia  morio.On the other hand, if this interpretation of the wing venation is incorrect, it may habitually resemble  Bibio  giganteus. Pongracz (1928: 183)considered  Bibio morioand  Bibio incrassatusas probable synonyms.