1	1st abdominal ventrite with two lateral striae (outer may be slightly abbreviated or curved behind metacoxa)	2
–	1st abdominal ventrite with one lateral stria, rarely with fragments of an additional, outer stria	6
2	Outer lateral stria of 1st abdominal ventrite curving behind metacoxa; inner subhumeral elytral stria absent	3
–	Lateral striae of 1st abdominal ventrite parallel; inner subhumeral stria present or absent	4
3	Outer subhumeral stria not complete, either present only in apical half or with short basal fragment; Central America	Operclipygus gilli sp. n.
–	Outer subhumeral stria more or less complete, may be faintly abbreviated at apex, but never interrupted at middle; South America	Operclipygus proximus sp. n.
4	Central portion of frontal stria absent, or represented by few remnant fragments (Fig. 49H); inner subhumeral elytral stria present as distinct stria, varied in length	Operclipygus prolixus sp. n.
–	Frontal stria complete (Fig. 53B); inner subhumeral stria absent or represented by few apical fragments	5
5	Frontal stria complete; frontal disk with distinct, dense fine punctation; 4th elytral stria complete or nearly so	Operclipygus punctifrons sp. n.
–	Frontal stria interrupted at sides; frontal disk with sparser ground punctation; 4th dorsal stria present in apical half only	Operclipygus distractus (Schmidt)
6	Body large, >4 mm, subdepressed, subquadrate (Fig. 53C); dorsal elytral striae fine, not strongly impressed; labrum wide, emarginate apically (Fig. 53D); epistoma strongly convex, frons depressed behind frontal suture; southeastern Brazil	Operclipygus latemarginatus (Bickhardt)
–	Body smaller, convex to subdepressed; dorsal striae strongly impressed toward apices; labrum narrower, not distinctly emarginate apically; epistoma not much more strongly convex than frons	7
7	Pygidium completely lacking marginal sulcus	Operclipygus plicatus (Hinton)
–	Marginal sulcus of pygidium present, though it may be weak and/or fragmented toward base	8
8	Anterior marginal pronotal gland openings close together, outer about half as far from inner as outer is from anterior pronotal corner (Fig. 47C)	9
–	Anterior marginal pronotal gland openings further apart, outer nearly twice as far from inner as it is from anterior pronotal corner	13
9	Body strongly convex (Fig. 50C), elytra elevated above pronotum in lateral view, interval between subhumeral and 1st elytral striae strongly convex relative to interval between 1st and 2nd dorsal striae; anterior pronotal angles turned downward, approximately vertical next to head	10
–	Body less strongly convex, elytral-pronotal profile more or less even; subhumeral elytral interval only slightly more strongly convex than 1st-2nd strial interval; anterior pronotal angles at least slightly oblique next to head	12
10	Pronotal disk lacking coarse lateral punctures; anterior pronotal margin strongly projecting above head	Operclipygus inflatus sp. n.
–	Pronotal disk with distinct coarse lateral punctures; anterior pronotal margin no more than weakly projecting above head	11
11	Outer subhumeral stria present in apical half and generally with additional, detached basal fragment; 4th elytral stria longer, generally present on apical two-thirds (Fig. 50A)	Operclipygus impressistrius sp. n.
–	Outer subhumeral stria present in apical half only, without basal fragment; 4th elytral stria shorter, present on less than apical half	Operclipygus farctissimus sp. n.
12	Outer subhumeral stria most often complete to base, rarely interrupted or abbreviated; inner subhumeral stria usually represented by few apical fragments; pygidium depressed along basal margin, with deep, coarse punctures interspersed with dense, fine ground punctation	Operclipygus distinctus (Hinton)
–	Outer subhumeral stria present in apical half only; inner subhumeral stria not evident; pygidium usually flatter, with coarse punctures not as large or dense	Operclipygus atlanticus sp. n.
13	Marginal mesoventral stria complete along anterior margin	14
–	Marginal mesoventral stria interrupted for some distance at middle	15
14	Body frequently appearing faintly bicolored, with rufescent elytra and darker pronotum (Fig. 47A), rounded, moderately convex; frontal stria interrupted over antennal bases	Operclipygus subrufus sp. n.
–	Body unicolorous, rufescent to rufobrunneus, more elongate, subdepressed; frontal stria complete	Operclipygus farctus (Marseul)
15	Apical margin of elytron with series of small punctures; ground punctation of pygidium generally sparse (Fig. 46D); sides of pronotal disk with distinct coarse punctures	Operclipygus bidessois (Marseul)
–	Apical margin of elytron lacking punctures; pygidium with moderately dense ground punctation; frontal stria interrupted over antennal bases; sides of pronotum with only faint lateral punctures (Fig. 47F)	Operclipygus petrovi sp. n.