Stenus Latreille 1796

Key to Stenus species of Shenzhen City

1 Legs with tarsomeres IV simple.......................................................................... 2

- Legs with tarsomeres IV distinctly bilobed................................................................. 5

2 Elytra each with an orange spot............................................................. S. tenuipes Sharp

- Elytra entirely black................................................................................... 3

3 Large species, BL: 4.8–5.5 mm ....................................................... S. formosanus L. Benick

- Small species, BL: 3.0–4.0 mm.......................................................................... 4

4 Abdominal tergites of segments III–V without longitudinal basal carina.............................. S. eurous Puthz

- Abdominal tergites of segments III–V with four longitudinal basal carinae............. S. melanarius melanarius Stephens

5 Abdominal segments with long and suberect setae.......................................... S. wutongshanus sp. n.

- Abdominal segments with short and recumbent setae........................................................ 6

6 Abdominal segments IV–VI with paratergites............................................................... 7

- Abdominal segments IV–VI without paratergites............................................................ 9

7 Head with very large eyes, average distance between eyes at most half the width of head....... S. bivulneratus Motschulsky

- Head with smaller eyes, average distance between eyes broader than half the width of head.......................... 8

8 Legs with knees distinctly darken, punctation of entire body sparser and less confluent................ S. stigmatias Puthz

- Legs with knees inconspicuously darken, punctation of entire body denser and more confluent................................................................................................. S. abdominalis abdominalis Fauvel

9 Abdominal segments bicolored......................................................................... 10

- Abdominal segments entirely black...................................................................... 11

10 Pronotum reddish, elytra blackish with basal and apical margins reddish............... S. flavidulus paederinus Champion

- Pronotum black, elytra black with pair of large orange spots..................................... S. frater L. Benick

11 Abdominal tergite X concaved apicomedially, head and pronotum without impunctate patch........... S. spurius L. Benick

- Abdominal tergite X rounded apically, head and pronotum with impunctate patches...... S. piliferus piliferus Motschulsky