1	Dorsum distinctly dull, uniformly dark pinkish brown, finely and very closely punctate; 5.5-6 mm. (FL; Bahamas, Caymans, Dominican Republic2, Cuba)	Pseudaptinus cubanus
–	Dorsum shiny, rufotestaceous to plain dark brown, more coarsely punctate in most species	2
2	Antennomeres 4-10 squarish, as long as wide (L/W = 1)	3
–	Antennomeres 4-10 distinctly elongated (L/W > 1)	4
3	Elytral striae rather irregularly but seriately punctate except apically, the punctures much coarser than those of the intervals; pronotum narrower and basal angles more minutely prominent; dorsum dark (reddish to blackish brown) usually with head and elytral disc darkest; eye prominent (E/T = 2); mostly 4.2-5 mm (southeastern US quadrant: AL, AR, FL, GA, LA, MS, NC2, eastern OK 1, 2, SC, TN2, eastern TX1, VA2; Cuba)	Pseudaptinus pygmaeus
–	Elytral striae not evidently seriately punctate, not more coarsely punctate than intervals; pronotum broader, basal angles more broadly prominent; uniformly reddish to dark brown; 5-6 mm. (FL, southeastern TX1; Caymans, Cuba, Dominican Republic2)	Pseudaptinus deceptor
4	Body length less than 5 mm; dorsum uniformly rufotestaceous; head small, distinctly narrower than pronotum; eyes rather small and flattish; elytra with striae poorly defined, intervals flat; location in southern California; 4.75 mm. (CA)	Pseudaptinus microcephalus
–	Body length usually at least 5 mm; combination not as above	5
5	Elytra with posterior sutural dark cloud; middle antennomere ratio L/W = 1.75-2	6
–	Elytra without dark cloud; middle antennomere ratio L/W various	8
6	Body length ≥ 6 mm; elytral intervals flat to slightly convex, densely punctate; E/T = 1.5 with temples gently curved; middle antennomeres with L/W = 2; dark sutural cloud distinct against rufotestaceous dorsum; 6-7 mm.(southwestern US quadrant: AZ, CA, NM, NV, OK2, TX; Mexico1)	Pseudaptinus horni
–	Body length ≤ 6 mm; elytral intervals distinctly convex, sparsely and finely punctate; middle antennomeres with L/W = 1.75; sutural cloud often less distinct	7
7	Body length usually ≤ 5.5 mm; eyes larger; temples strongly curved, shorter than in Pseudaptinus horni (E/T = 1.5-1.9); sutural cloud more often faint or absent; mostly ferruginous with forebody sometimes darker; 4.7-5.5 mm. (southeastern US quadrant: AL2, AR, DC, FL, GA2, LA, OK2, PA2, SC, TX; Bahamas, Cuba, Dominican Republic, Jamaica, Mexico1 )	Pseudaptinus dorsalis
–	Body length 5.6-6 mm; eyes smaller; temples gently curved, longer against small eyes as compared to Pseudaptinus horni (E/T = 1-1.5); more uniformly brownish; (south-central US: MS, TX; Mexico)	Pseudaptinus hoegei
8	Body length ≥ 6 mm; middle antennomere ratio L/W = 2; see also key step #6	Pseudaptinus horni, an occasional specimen which lacks the sutural dark cloud on elytra. This variant occurs most notably in southern California where the population is entirely rufous (Van Dyke, 1926)
–	Body length ≤ 6 mm except for Pseudaptinus nobilis; middle antennomere ratio either much longer (L/W = 3) or shorter (L/W ≤ 1.75)	9
9	Middle antennomeres markedly prolonged with L/W = 3; eye size and convexity both markedly reduced; eye diameter distinctly shorter than temple (E/T < 1); head black, contrasts with dark red-brown dorsum; punctures on forebody coarse and quite dense; elytra stretched lengthwise, slightly oval, not strongly narrowed at shoulders; 6.5-7 mm. (TX - Live Oak Co. is new US record1; Mexico)	Pseudaptinus nobilis
–	Middle antennomeres short with L/W ≤ 1.75; eyes larger with E/T ≥ 1; head not black; body length less than 6.5 mm	10
10	Eyes appear markedly enlarged against very short temples (E/T = 3); middle antennomeres shorter (L/W = 1.25); yellow-brown; 4.8-5.1 mm. (Mexico)	Pseudaptinus simplex
–	Eyes relatively smaller (E/T < 2); middle antennomeres longer; body usually larger	11
11	Dorsum uniformly ferruginous (reddish); eyes appear flatter and smaller against long temples (E/T = 1); middle antennomeres L/W = 1.5; 5.1 - 5.5 mm. (western US: AZ1, 2, CA, OR, TX)	Pseudaptinus rufulus
–	Dorsum not uniformly reddish, often darker brownish; eyes larger relative to temples; middle antennomeres L/W = 1.75	12
12	Body length usually ≤ 5.5 mm; eyes relatively large with temples shorter, strongly curved (E/T = 1.5-1.9); see also key step #7	Pseudaptinus dorsalis
–	Body length 5.6-6 mm; eyes relatively small with temples longer, gently curved (E/T = 1-1.5); see also key step #7	Pseudaptinus hoegei