Key to species of Chlorops from Palearctic China

1. Ocellar triangle dark brown entirely....................................................................... 2

- Ocellar triangle yellow with black spot, or brown with yellow lateral margins or posterior corners...................... 3

2. Gena with a narrow black region on lower margin; scutum yellow entirely, covered with short setulae and pale pollen.............................................................................................. C. oralis (Duda)

- Gena yellow entirely; scutum yellow, but brown posteriorly, shinning, covered with long setulae.... C. liupanshanus sp. nov.

3. 3rd antennal segment enlarged, black, with a reddish spot basally; arista black, with black basal segment.................................................................................................. C. extraneus Wiedemann

- 3rd antennal segment or arista is different from mentioned above................................................ 4

4. Katepisternum with reddish-yellow lower portion............................................................ 5

- Katepisternum with black lower portion....................................................................6

5. Ocellar triangle brown, with yellow lateral margins and posterior margin, with a black medial sulcus and a yellow sulcus on each lateral margin, and also with a yellow spot on each lateral margin of ocellar tubercle; scutum with 5 black stripes........................................................................................... C. trisetifer sp. nov.

- Ocellar triangle yellow, with a small black spot on anterior apex, and with a medial brownish bridge; scutum yellow with 5 reddish-yellow stripes, the median stripe black anteriorly...................................... C.rufinus Zetterstedt

6. Ocellar triangle yellow, with a black spot in leaf shape covering most part of triangle and contended with ocellar tubercle, and with a medial sulcus attending to anterior margin of frons, yellow anteriorly and black posteriorly; anepisternum covered with tiny yellow setulae.................................................................... C. flavipalpus sp. nov.

- Ocellar triangle different from mentioned above; anepisternum bare............................................. 7

7. Ocellar triangle yellow, main portion of triangle only two-thirds as long as frons, with a brown spot on anterior apex, and also with a medial black sulcus from ocellar tubercle to anterior margin of frons; 3rd antennal segment black..................................................................................................... C. gansuensis sp. nov.

- Ocellar triangle yellow, main portion of triangle nearly attending to anterior margin of frons, dark brown centrally in leaf shape contended with ocellar tubercle, with a medial black sulcus and a yellow spot on each lateral margin of ocellar tubercle; 3rd antennal segment brownish dorsally and distally, yellow ventrally and basally................... C. xinjiangensis sp. nov.