Key to species of Laccomimus
1. Prosternal process, in lateral view, saddle-shaped, placed below (if ventral side is turned upside) metaventrite level (Figs 24– 27); prosternum protruding anteriorly (Figs 24–27); lobes of metacoxal processes ending in long, acuminate spine in both sexes (Fig. 38)........................................................................................ 2
- Prosternal process, in lateral view, straight or almost so, on same level as metaventrite (Figs 20–22; 29–31); prosternum not protruding anteriorly (Figs 20–22; 29–31); lobes of metacoxal processes rounded or at most angulated (Figs 37; 39–40), otherwise ending in spine only in males and angulated in females (Figs 32–36)........................................ 4
2. Elytra variegate, with irregular patterns arranged on whole surface (Fig. 61); aedeagus as in Fig. 86 .......... L. variegatus
- Elytral colouration different............................................................................. 3
3. Elytra uniformly brownish; median lobe of aedeagus not expanded apically and left paramere strongly narrowed in apical half (Fig. 87); stalked suction palettes on pro- and mesotarsi normally developed.............................. L. spinosus
- Elytra dark-brown, with distinct subbasal, lateral, and subapical yellow bands as in Fig. 62; median lobe of aedeagus with flat leaf-like apical expansion and left paramere broad, gradually narrowed at tip (Fig. 88); stalked suction palettes on pro- and mesotarsi very broad (Figs 47–48)............................................................... L. amazonas
4. Males: lobes of metacoxal processes ending in acuminate spine (Fig. 32); both protarsal claws simple, equal in shape. Females: lobes of metacoxal processes more or less acute, but not ending in spine (with some extremely rare exceptions) (Figs 33–36); gonocoxal blades two-toothed and ramus with teeth spaced and moderate in size (Fig. 116)................... L. distinctus
- Lobes of metacoxal processes rounded or at most obtusely angulated in both sexes; outer protarsal claw of males scimitarshaped, different from simple inner claw.................................................................. 5
5. Females with two-toothed gonocoxal blades and ramus with fine and serrate teeth (Fig. 117); males with long and stiff median lobe, ending in very small, button-like expansion and left paramere distinctly bisinuate along dorsal side (Fig. 85)...................................................................................................... L. malkini
- Females with one-toothed gonocoxal blades and ramus with large and spaced teeth (Figs 118; 120); males with apical expansion of median lobe well developed and left paramere at most with one sinuation along dorsal side...................... 6
6. Median lobe of aedeagus straight, almost lacking distinction between base and distal portion, gradually narrowed to apex, ending in wide and flat expansion (Figs 90; 105–106); lobes of metacoxal processes ending in obtuse but clear angulation (Fig. 41)................................................................................................... 7
- Median lobe of aedeagus with base and distal portion visibly distinct, together forming an angle or a curve, apex ending in small expansion (Figs 89; 91–104); lobes of metacoxal processes rounded or very poorly angulated (Figs 39–40)......... 8
7. Aedeagus (Fig. 90): median lobe distally steam-like, with very wide apex, broadly rounded only on dorsal side; left paramere quite blunt, rounded apically..................................................................... L. youngi
- Aedeagus (Figs 105–106): median lobe distally narrowed but not steam-like, apex somewhat narrower, broadly rounded on both sides or only on ventral side; left paramere slender, with more acute apex............................. L. bolivari
8. Underside at least in part black or dark brown; apical expansion of median lobe of aedeagus typically bird head-like shaped (Fig. 103).................................................................................... L. bordoni
- Underside always uniformly reddish or testaceous; apical expansion of median lobe of aedeagus rounded............... 9
9. Apex of prosternal process acuminate or acutely rounded (Figs 67–68); species known from Florida to Costa Rica ........ 10
- Apex of prosternal process clearly rounded (Fig. 69); species known from Panamá to Argentina ....................... 11
10. Size smaller (TL: 1.80 –2.10 mm); distal portion of median lobe of aedeagus straight, with dorsal and ventral sides almost parallel (Fig. 104).............................................................................. L. spangleri
- Size larger (TL: 2.10–2.35 mm); distal portion of median lobe of aedeagus visibly sinuate on both sides, especially ventral one (Figs 91–93)................................................................................. L. pumilio
11. Distal portion of median lobe of aedeagus with both sides sinuate, especially ventral one; apex ending in button-like, almost bulbous expansion (Figs 94–102)................................................................ L. alvarengi
- Distal portion of median lobe of aedeagus with both sides almost straight, regularly converging to apex, which ends in a wider, laterally flattened expansion (Fig. 89)........................................................... L. improvidus