Key to the species of Isoneuromyia Brunetti known from China

1. Occiput predominantly orange to yellow with darker occipital triangle ..................................................... 2

-. Occiput predominantly brownish black to black ......................................................................................... 3

2. Mesonotum with three distinct dark stripes; antennal flagellomeres brownish black .... formosana (Okada)

-. Mesonotum with three stripes, median stripe orange and two admedian stripes black (Fig. 1); antennal flagellomeres yellowish orange ............................................................... sinica Xu, Cao et Evenhuis, n. sp.

3. Veins M2 and CuA1 reaching wing margin (Fig. 6); only tergites IV–V orange .......................................... ............................................................................................................ completa Xu, Cao et Evenhuis, n. sp.

-. Veins M2 and CuA1 not reaching wing margin; tergites IV–V not as above.............................................. 4

4. Abdomen predominantly black with some paler markings ......................................................................... 5

-. Abdomen with more uniform coloration, either black or brownish yellow; gonostyli with two large teeth ......................................................................................................................................... semirufa (Meigen)

5. Gonostyli reduced, apex with only one dark tooth (Fig. 11); paramere strong, in lateral view (Fig. 12) shaped like a broom, with very dense black short hairs apically .......... singula Xu, Cao et Evenhuis, n. sp.

-. Gonostyli normal in size, with two dark teeth apically (Fig. 13), two minute dark sclerotized teeth in between large darkly sclerotized ones .......................................... wolongensis Xu, Cao et Evenhuis, n. sp.