Plecia akerionana, n. sp., is described from the Green River Formation, Colorado, and diagnosed with P. minutula Rice, P. myersi Peterson, and P. rhodopterina Cockerell. Plecia intermedia (Scudder), the genotype of Mycetophaetus, and Plecia creedensis James are transferred to the genus Penthetria, and Hesperinus immutabilis Melander is transferred to Plecia.
Fitzgerald, Scott J.
"A new species of Plecia from the Green River Formation and new combinations of fossil Bibionidae (Diptera),"
Great Basin Naturalist: Vol. 59
, Article 10.
Available at: http://scholarsarchive.byu.edu/gbn/vol59/iss2/10