1	Elytral disc plurisetose	2
1’	Elytral disc with setiferous punctures in interval 3, or sometimes also in interval 5	5
2(1)	Profemur plurisetose	3
2’	Profemur with the usual setae	4
3(2)	Pronotal disc plurisetose (along margin and on disc). Habitus as in Fig. 48. USA	Semiardistomis puncticollis(Dejean)
3’	Pronotal disc with the usual 2 pairs of marginal setae. Habitus as in Fig. 44. South America	Semiardistomis pilosellus (Kult)
4(2’)	Pronotal disc plurisetose along margin. Habitus as in Fig. 55. USA	Semiardistomis viridis (Say)
4’	Pronotal disc with the usual 2 pairs of marginal setae. Habitus as in Fig. 54. Mexico	Semiardistomis propinquus (Putzeys)
5(1’)	Elytron with two setiferous punctures on interval 3; humerus rounded; brachypterous. Habitus as in Fig. 47 Guadeloupe	Semiardistomis laevistriatus (Fleutiaux & Sallé)
5’	Elytron with three or more setiferous punctures on interval 3; macropterous	6
6(5’)	Elytron with three setiferous punctures on interval 3	7
6’	Elytron with more than three setiferous punctures on interval 3	12
7(6)	Elytral striae impunctate. Habitus as in Fig. 52. South America	Semiardistomis pallipes (Dejean)
7’	Elytral striae punctate	8
8(7’)	Elytral disc with isodiametric mesh pattern	9
8’	Elytral disc smooth	10
9(8)	Elytral striae impressed only in basal fifth, punctures deep along three-quarters of elytra, surface completely covered with isodiametric mesh pattern. South America	Semiardistomis deletus (Putzeys)
9’	Elytral striae obliterated in apical third, punctures moderately deep, surface with isodiametric mesh pattern, evanescent in central area of elytral disc in some specimens. South America	Semiardistomis flavipes (Dejean)
10(8’)	Elytral striae obliterated in apical fifth, punctures moderately deep. Habitus as in Fig. 51. West Indies	Semiardistomis cyaneolimbatus (Chevrolat)
10’	Elytral striae impressed only in basal fifth	11
11(10’)	Elytral punctures deeply impressed in basal two-thirds of elytra. Habitus as in Figs 1, 2. Central America	Semiardistomis labialis (Chaudoir)
11’	Elytral punctures moderately impressed in basal third of elytra. Southern South America	Semiardistomis semipunctatus (Dejean)
12(6’)	Elytral disc surface completely covered with isodiametric mesh pattern. Habitus as in Fig. 46. South America	Semiardistomis maindroni (Kult)
12’	Elytral disc surface smooth	13
13(12’)	Elytral striae complete; impunctate	14
13’	Elytral striae incomplete	17
14(13)	Front between antennal lobes with transverse rugae. Habitus as in Fig. 50. Southern Brazil	Semiardistomis rugosus
14’	Front between antennal lobes smooth	15
15(14’)	Elytron with five setiferous punctures on interval 3; body size more than 7 mm. Habitus as in Fig. 49. Peru	Semiardistomis major n. sp.
15’	Elytron with four setiferous punctures on interval 3; body size less than 6 mm	16
16(15’)	Pronotum markedly cordate, 1.25 times wider than long; humeri square, sides subparallel. Habitus as in Fig. 37. Colombia	Semiardistomis cordicollis (Putzeys)
16’	Pronotum subcordate, 1.14 times wider than long; shoulders rounded. Habitus as in Fig. 38. South America.	Semiardistomis exspectatus n. sp.
17(13’)	Elytron with eight setiferous punctures in interval 3	18
17’	Elytron with four setiferous punctures in interval 3	19
18(17)	Elytron with three setiferous punctures in interval 5. Habitus as in Fig. 39. Brazil	Semiardistomis darlingtoni (Kult)
18’	Elytron with interval 5 asetose. Habitus as in Fig. 40. South America	Semiardistomis subglabra (van Emden)
19(17’)	Elytral striae 3,4,5 and 6 impressed in basal half of disc, stria 2 present. Body length around 4 mm. Habitus as in Fig. 45. South America	Semiardistomis jedlickai (Kult)
19’	Elytral striae 3, 4, 5 and 6 impressed in basal third of disc, stria 2 absent. Body length around 6 mm. Habitus as in Fig. 41. South America	Semiardistomis glabratus (Putzeys)