20a The body is pedunculate, the anterior part of mesothorax with extreme base of elytra strongly constricted, forming a peduncle on which the scutellum is situated. 30
20b Body not pedunculate, or if slightly so, the scutellum reaches the level of the shoulders and usually extends between the suture of the elytra. 40
30a Mandibles strongly protruding, upper surface without pronounced metallic lustre. Promecognathus
30b Mandibles less developed. Upper surface with ± pronounced metallic lustre. Zacotus
40a Each elytron with at least 11 well impressed striae, ± regular striae at least basally, and without ridges or tubercles. 50
40b Each elytron with less than 11 complete striae (abbreviated scutellar striae not counted) or rows of punctures, or ± irregularly sculptured, or smooth. 60
50a Head very narrow (less than half as wide as prothorax), and without suddenly constricted neck; mandibles with two sharp teeth near apex; antennal segments 2-4 with short setae; size variable. Scaphinotus
50b Head wider than half of prothorax; head with suddenly constricted neck; mandibles without teeth; antennal segments 2-4 with very long setae; less than 9 mm long. Loricera
60a Head with two setigerous supra-orbital punctures dorsomedially to each eye. 70
60b Head with one setigerous supra-orbital puncture dorsomedially to each eye. 120
70a Sutural stria of elytron "recurrent" at apex; size not above 6.5 mm Trechus
70b Sutural stria not recurrent; size is usually larger 80
80a Labrum asymmetrical and cleft almost to base; size 6.5mm or less. Badister
80b Labrum entire or with moderately emarginate anterior margin; size variable. 90
90a Elytra with two or more setigerous dorsal punctures on third interval. 95
90b Elytra with one or no setigerous dorsal punctures. 110
95a Face each side with pair of longitudinal grooves, joined by median impression (see figure below). Blethisa
95b Face without without this pattern of longitudinal grooves. 100
100a Claws denticulate or serrate; mentum without tooth. Calathus
100b Claws smooth; mentum with tooth Platynus
110a Penultimate segment of labial palp plurisetose; mandibles very short Amara
110b Penultimate segment of labial palp bisetose; mandibles longer and more pointed. Pterostichus
120a Elytra with ± irregular sculpture, consisting of foveae, ridges, confluent tubercles. 130
120b Each elytron with ± regular, striae, sometimes obliterated or interrupted or unequally spaced (rarely only sutural stria complete); intervals sometimes foveate but without ridges or tubercles. 150
130a Head very narrow; mandible with two sharp teeth internally 140
130b Head broader; mandible without teeth. Carabus
140a Labrum with 6 setae; tarsi pubescent dorsally. Scaphinotus
140b Labrum with 4 setae; tarsi glabrous above. Cychrus
150a Prothorax with long seta at hind angle; at least third or fourth elytral interval with two or more dorsal punctures. Nebria
150b Prothorax without seta at hind angle; elytra with one or no dorsal puncture on third interval. 160
160a Mandibles broadly explanate laterally; protibia without cleaning organ internally. Leistus
160b Mandibles not dilated; protibia with cleaning organ internally. 170
170a Penultimate segment of labial palp with many setae Harpalus
170b Penultimate segment of labial palp only with 2 (rarely 3) setae Bradycellus
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For information about this page: John T. Longino longinoj@evergreen.edu
Last modified: Blethisa added by J. Longino, 13 October 1998.