Key to the Calosoma depressicolle complex

1 Apex of aedeagus flag-shaped (characteristic of entire subgenus) and with transverse process conspicuous in vertical plane (Plates 3–4: Figs. 10, 13, 14–16, 18, 19. Plate 5: Fig 22 B, C; Fig 23 A, B; Fig 24); N Colima, S Jalisco, Michoacán................................................................................................. flohri group 2.

- Apex of aedeagus also flag-shaped but without transverse process in vertical view (Plates 1–2: Figs. 1, 2, 5, 7–9. Plates 5–6: Fig. 22 A, D; Fig. 23 C–E). Pronotum smooth or finely punctured at base and sides; Distrito Federal, México, Morelos........................................................................................ depressicolle group 6.

2 (1) Transverse process of aedeagus short and arcuate (Plate 4: Figs. 18, 19; Fig. 22 C; 23 B); NE Michoacán........ C. lesnei .

- Transverse process of aedeagus longer, trapezoidal (Plates 3–4: Figs. 10, 13, 14–16. Plates 5–6: Fig. 22 B; Fig. 23 A; Fig. 24); N Colima, S Jalisco, W Michoacán................................................... C. flohri; four subspecies 3.

3 (2) Entire head and pronotum densely punctured; body smaller, 17.5– 21 mm (Plate 3: Fig. 10)................ C. flohri flohri .

- Head and pronotum smooth or coarsely punctured only near base.

4 (3) Elytral sculpture smooth or only coarsely punctured, without visible intervals, body smaller, 18–21 mm (Plate 3: Figs. 12–14)....................................................................................... C. flohri gebieni .

- Elytral sculpture well expressed, with visible intervals, body larger, 20–24 mm.

5 (4) Head and pronotum near base coarsely punctured (Plate 4: Figs. 16, 17)........................... C. flohri zirostense .

- Head and pronotum near base almost smooth (Plate 4: Fig. 15)................................. C. flohri colimaense .

6 (1) Body smaller and wider (16–18 mm). Aedeagus with rounded termination of diameter so small that it appears pointed unless magnified (Plate 2: Figs. 7, 8. Plates 5–6: Fig. 22 D; Fig. 23 E), and flag-shaped thickening weakly indicated, discernible only under magnification. Elytra with large, irregularly spaced punctures which interrupt neighboring, finely punctured intervals. Only C México: Volcán Nevado de Toluca.......................................................... C. altipeta .

- Body somewhat larger (length of smallest specimens exceeds 17 mm) and narrower; apex of aedeagus with flag-shaped thickening visible without magnification (Plates 1–2: Figs: 1–6, 9).................................................. 7.

7 (6) Apex of aedeagus in lateral view with pronounced step-like thickening; body larger, 20–24 mm (Plate 2: Fig. 9); E México: Río Frío; W Puebla............................................................................ C. sylvestre .

- Apex of aedeagus with weak thickening only, which viewed laterally narrows toward terminus gradually, without any step-like break (Plates 1–2: Figs. 1, 2, 5. Plates 5–6: Fig. 22 A; Fig. 23 C, D); body smaller, 16–20 mm; W, C and SE areas of México, E Michoacán............................................................ C. depressicolle, two subspecies ..... 8.

8 (7) Pronotum completely smooth, including sides and base. Elytral striae more regular, intervals flat or slightly convex, without scattered punctures or in some specimens with a few punctures only on sides (Plate 1: Figs. 1–4. Plate 6: Fig. 23 C); C México, Distrito Federal, Morelos........................................................ C. depressicolle depressicolle .

- Pronotum with a few punctures on sides and base. Elytral striae slightly disarrayed near apex (Plate 2: Figs. 5, 6. Plates 5–6: Fig 22 A; Fig 23D), deeper; intervals convex, with large, scattered punctures; foveae not always obvious; W México, E Michoacán............................................................................... C. depressicolle asper .