This keys as Pegasomyia abaureus. Very similar to Stonemyia, but R4 has a short vein near its base (the "appendix", as per MND). This was formerly in Pilimas, but that genus is now considered a synonym of Stonemyia, resulting in the creation of a new genus, Pegasomyia, for this species and P. ruficornis. Males of these two species are easily told apart by the color of the thorax and antennae, yellow=abaureus, brown=ruficornis.

Both species are reported from cismontane California. Biology of this genus is unknown, but both sexes have been observed on flowers.

(34.631389 , -120.000833), 843 feet

Burger, J.F., 1985. A redefinition of Stonemyia (Diptera: Tabanidae) and designation of a new genus, Pegasomyia, from western North America. Psyche, 92(1), pp.119-124.

Middlekauff, W.W. and Lane, R.S., 1980. Adult and immature tabanidae (Diptera) of California (Vol. 22). Univ of California Press.