Identification
Technical key to North American genera of CYCHRINI after American Beetles (2001).
Most anatomic details cited here will not be visible with routine field photography.
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1.
Suture between proepisternum and proepimeron present, at least in medial half of pleuron;
Base of deep labral emargination with two (subgenus Maronetus) or four setae;
Penultimate labial palpomere with two (subgenus Maronetus) or more setae;
[Clypeus with distal border not emarginated] ==> Scaphinotus
Suture between proepisternum & proepimeron absent, but area representing proepimeron densly punctate or not;
Base of deep labral emargination bisetose;
Penultimate labial palpomere with two or more setae ==> couplet 2
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2.
Penultimate labial palpomere bisetose;
[Clypeus with distal medial border emarginated];
Range: eastern North America ==> Sphaeroderus
Penultimate labial palpomere plurisetose;
Range: northwestern North America ==> Cychrus
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