Elaphrus Fabricius 1775

Key to subgenera of Elaphrus (revised from Goulet, 1983)

1. Fringe of setae on posterior margin of pronotum not reaching posterior angle. Suture between proepisternum and proepimeron evident. Males with first four tarsomeres slightly expanded and with spongy pubescence ventrally.............................................................................................................................................2

- Fringe of setae on posterior margin of pronotum extended to posterior angle. Suture between proepisternum and proepimeron not evident. Males with first three tarsomeres slightly expanded and with spongy pubescence ventrally, or not expanded and without spongy pubescence....................................................3

2. Maxillary palpomere 3, half as long as palpomere 4. Disc of prosternum and lateral portion of metasternum setose. Elytral pits with one to six irregularly arranged punctures. Microsculptures on elytra strongly convex and widespread .............................................................................................Arctelaphrus Semenov

- Maxillary palpomere 3, one-third as long as palpomere 4. Disc of prosternum and lateral portion of metasternum asetose. Elytral pits with at least eight regularly distributed punctures. Microsculptures on elytra at most slightly convex and not covering entire surface ......................................Neoelaphrus Hatch

3. Lateral margin of pronotum strongly projected in the middle to form a distinct middle angle, with midlateral seta present at angle. Submentum with 10 or 12 setae. Anterior ridge of metepisternum distinct at inner half. Abdominal sternum VII with 6–10 setae on posterior margin ....... Sinoelaphrus new subgenus

- Lateral margin of pronotum not projected in the middle, and without midlateral seta. Submentum with 6 or 8 setae. Anterior ridge of metepisternum absent. Abdominal sternum VII with 2 or 4 setae on posterior margin..........................................................................................................................................................4

4. Clypeus with four to six setigerous punctures. Disc of prosternum and process of mesosternum setose. Trochanters of foreleg and midleg with three setigerous punctures. Coxa of hindleg with setae covering surface ............................................................................................................................. Elaphrus Fabricius

- Clypeus with two setigerous punctures. Disc of prosternum and process of mesosternum asetose. Trochanter of foreleg with two, that of midleg with one or two setigerous punctures. Coxa of hindleg with setae restricted to mesial half of surface ................................................................... Elaphroterus Semenov