Key to species of Ardistomina in America, north of Mexico, and " Ardistomis " morio

1 Proepipleura not visible from above; metacoxae contiguous medially; pleurite VII without small projection; body length around 8.5 mm and elytra without spot ............. ........................................................................................... " Ardistomis " morio (Dejean)

­ Proepipleura visible from above; metacoxae separated medially; pleurite VII with small projection fitted into preapical elytral plica (Fig. 22); body length 4.8–8.0 mm and elytra with preapical rufous spot if over 7.0 mm.................................................... 2

2 Metasternum with row of punctures along metepisternal suture; clypeus with prominent lateral lobes (Fig. 19) ................................. Aspidoglossa subangulata (Chaudoir)

­ Metasternum without row of punctures along metepisternal suture; clypeus with lateral lobes distinct but not prominent (Fig. 20), or indistinct (Fig. 21).......................... 3

3 Proepisternum with longitudinal band of sculpture (Fig. 27); side of pronotum with only 2 setae; elytral striae impunctate (in the species treated) [genus Ardistomis]....... 4

­ Proepisternum without band of sculpture; side of pronotum with several setae (in the species treated); elytral striae punctate, each puncture bearing seta (in the species treated) [genus Semiardistomis] .................................................................................... 5

4 Elytron without metallic lustre, with preapical rufous spot; elytral interval 3 with 7–11 setae ................................................................................. Ardistomis obliquatus Putzeys

­ Elytron with blue­green lustre, without preapical spot; elytral interval 3 with 5 (–6) setae .................................................................................. Ardistomis schaumii LeConte

5 Frons with 2 supraorbital setae on each side; pronotal disc without setae...................... ............................................................................................ Semiardistomis viridis (Say)

­ Frons with 5–7 supraorbital setae on each side; pronotal disc with setae....................... .............................................................................. Semiardistomis puncticollis (Dejean)