Specimens were provided by the following institutions:

AKTC Alexey Tishechkin Collection, Santa Barbara, USA

AMNH American Museum of Natural History, New York, USA

BDGC Bruce Gill Collection, Ottawa, Canada

BMNH Natural History Museum, London, UK

CASC California Academy of Sciences Collection, San Francisco, USA

CEMT Coleção de Entomologia, Universidade Federal do Mato Grosso, Cuiabá, Brazil

CHFP Fabio Penati Collection, Genoa, Italy

CHJG Jeffrey P. Gruber Collection, Madison, USA

CHND Nicolas Dégallier Collection, Paris

CHPK Piet Kanaar Collection, Leiden, The Netherlands

CHPWK Peter Kovarik Collection, Columbus, USA

CHSM Slawomir Mazur Collection, Warsaw, Poland

CMNC Canadian Museum of Nature, Ottawa, Canada

CMNH Carnegie Museum of Natural History, Pittsburg, USA

CNCI Canadian National Collection of Insects, Ottawa, Canada

EMEC Essig Museum of Entomology, Berkeley, USA

ECOSUR El Colegio de la Frontera Sur, San Cristóbal de Las Casas, México

FMNH Field Museum, Chicago, USA

FSCA Florida State Collection of Arthropods, Gainesville, USA

GBFM Museo Fairchild, Universidad de Panama, Panama City, Panama

IAVH Instituto Alexander von Humboldt, Villa de Leyva, Colombia

INBIO Instituto Nacional de Biodiversidad, San Jose, Costa Rica

IRSNB Institut Royal des Sciences Naturelles de Belgique, Brussels, Belgium

LSAM Louisiana State Arthropod Museum, Baton Rouge, USA

LUND Entomological Museum of Lund University, Lund, Sweden

MACN Museo de Ciencias Naturales ‘Bernardino Rivadavia’, Buenos Aires, Argentina

MCZC Museum of Comparative Zoology, Harvard University, Cambridge, USA

MEL Museo Entomológico de León, Nicaragua

MHNLS Museo de Historia Natural La Salle, Caracas, Venezuela

MHNG Museum d’Histoire Naturelle, Geneva, Switzerland

MNHN Museum National d’Histoire Naturelle, Paris, France

MSCC Michael Caterino Collection, Santa Barbara, USA

MUSM Museo de Historia Natural, Universidad Nacional Mayor de San Marcos, Lima, Peru.

OUMNH Oxford University Museum of Natural History, Oxford, UK

RMNH National Natuurhistoisch Museum, Leiden, Netherlands

SBMNH Santa Barbara Museum of Natural History, Santa Barbara, USA

SEMC Snow Entomology Museum, University of Kansas, Lawrence, USA

TAMU Texas A&M University Collection, College Station, USA

UCONN University of Connecticut Insect Collection, Storrs, USA

UDG Universidad de Guadalajara, Guadalajara, Mexico

UFPR Universidade Federal do Paraná, Curitiba, Brazil

UNESP-IS Universdade Estadual Paulista, Faculdade de Engenharia de Ilha Solteira, Ilha Solteira, Brazil

UNL University of Nebraska State Museum, Lincoln, USA

USFQ Universidad San Francisco de Quito, Ecuador

USNM National Museum of Natural History, Washington, USA

WBWC William B. Warner collection, Phoenix, USA

ZMHB Zoological Museum of Humboldt University, Berlin, Germany

ZISP Zoological Institute, Russian Science Academy, Saint Petersburg, Russia

Characters of Operclipygus, terminology and variability

Much of the morphological terminology used is based on Wenzel and Dybas (1941), but modified to follow more recent treatments by Helava et al. (1985), Ôhara (1994), Kanaar (1997) and Lawrence et al. (2011). However, the species included here, and in other Exosternini have required the refinement of some existing terms, and introduction of a few new ones. The labeled illustrations provide an overview of our terminology for external (Figs 1–2) and male genitalic (Fig. 3) morphology.

Overall body shape – Body shapes vary considerably among the species of Operclipygus, varying in length/width ratio, roundness, whether narrowed more strongly toward the head or toward the pygidium, as well as in dorsoventral convexity. Body color and subtle texturing also show significant variation among species. All these characters of general appearance can be very useful in identification. At the same time they are difficult to describe, and best appreciated in photograph. We provide dorsal habitus photos for most species described in the paper, but we refer readers to online images for other perspectives.

Head – Informative characters of the head include varying completeness and shape of the frontal stria (Fig. 4). It is frequently interrupted at the middle (Fig. 4B) or doubly interrupted at the sides (Fig. 4C), occasionally both. It may be outwardly arcuate across the entire frons, sinuate over the antennal bases and straight in the middle, or rarely arched dorsad at the middle. Variation within species is usually minimal in these characters, although there are noted exceptions. The supraorbital stria may be present or absent, varies somewhat in degree of impression, and when present may be connected to the sides of the frontal stria or detached.

The convexity of the frons offers a number of useful characters, although these are difficult to adequately describe. Most often the frons and epistoma together are weakly depressed over most of the space between the eyes. There are a few species, or groups of species, like the Operclipygus impressifrons group, where this depression is markedly deeper (Fig. 28C). Alternatively, in a few groups, most notably the Operclipygus kerga group, the entire frontal area is flat to weakly convex (Fig. 11B).

We utilize a few characters of the labrum in the key and the descriptions, mainly the length/width ratio and the apical shape, which varies from weakly emarginate to weakly rounded. In many species the apical margin appears emarginate across the dorsal margin, but has a distinct process emerging from the ventral surface. This is frequently associated with a pronounced asymmetry in the emargination.

The only mouthpart characters we make regular use of are the presence and shape of basal teeth on the mandibles. The majority of species have a small subacute tooth at the base of the right mandible, but nothing on the left (Figs 4C, F). Where the left mandible bears a tooth it is generally larger and blunter than that on the right (Fig. 11B). It is rare, and taxonomically useful, to have both teeth present and more or less similar in appearance (Fig. 4E). There is relatively little variation in other mouthparts, and they are not detailed beyond the generic description, except in a couple of distinctive cases.

The antennal club exhibits some variation, although most of that is at higher levels in the tribe. Most Operclipygus have a similar club in which the basal annulus is weakly inwardly arcuate and interrupted, the middle annulus is weakly widened and densely setose in the middle of the dorsal and ventral surfaces, and the apical annulus is reduced to small setose patches on dorsal and ventral surfaces (Fig. 4G). The middle annulus is interrupted in numerous species, so that it appears to terminate in expanded setose patches (Fig. 4H). In a small number of species in the Operclipygus hospes group, there is a distinct round sensorium on the upper basolateral surface of the club (Fig. 4I) We have not made extensive use of these characters due to the difficulty of observing them clearly in the majority of specimens.

Pronotum – The pronotum offers a large number of characters informative for phylogenetic relationships and for species recognition. Perhaps the most significant are newly documented gland openings on the pronotal dorsum. External gland openings, while numerous in Histeridae, have not been well documented. They are in many cases easily homologized among disparate taxa, though a more thorough accounting is needed. Most Neotropical Exosternini exhibit two pairs of gland openings along the anterior pronotal margin. In a few groups, particularly in Operclipygus, the medial pair of these openings varies greatly in position, ranging from the plesiomorphic position along the margin behind the eyes (Fig. 5A) to the middle or even further posterad on either side of the pronotal disk (Fig. 5B, C). Several lineages can be easily diagnosed through their position. While at first these openings are not obvious, in most clean specimens they are readily visible.

The various striae of the pronotum are also very useful in recognizing species and groups of species. The marginal stria generally runs continuously along the front and sides of the pronotum, usually immediately dorsad the actual edge. In many species it is broadly interrupted behind the head (Fig. 5A), or occasionally simply weakened. In some members of the Operclipygus hamistrius group the marginal stria crosses the lateral margin near the anterolateral corner, descending to run along the ventral margin (Fig. 5D). In a few such cases there is a distinct, fine groove where it crosses the margin. What we call the lateral submarginal stria is generally (e.g. Ôhara 1994, Kanaar 1997) referred to simply as the lateral stria. However, in many Operclipygus this stria is continuous with a stria behind the anterior pronotal margin, and we prefer to refer to this entire stria as submarginal stria, with lateral and anterior portions. It is frequently interrupted behind the eye, with the ends of the anterior portion recurved for a variable distance posterad (Fig. 5B). This nearly always occurs in concert with the median pronotal gland openings being displaced posterad, suggesting a developmental relationship between them. We refer to the narrow portion of the pronotal disk, between the lateral marginal and submarginal striae as the pronotal bead.

Many Neotropical Exosternini exhibit a distinct prescutellar impression, although this is relatively rare in Operclipygus species. Some groups, however, do consistently possess one. In many members of the Operclipygus hospes and Operclipygus dubius groups the prescutellar impression is distinctly elongate, frequently longer than the scutellum, occasionally flame-shaped, and a few species (Operclipygus dubitabilis group) have a small punctiform impression. However, Operclipygus almost never exhibit a prescutellar impression that is distinct and elongate oval (as in many Phelister) and never larger, approaching semicircular (as in several species related to ‘Phelister’ blairi Hinton).

A number of species exhibit what are commonly termed plicae (Fig. 5E). These are a pair of more or less linear depressions extending forward from the base of the pronotum to about its midpoint, usually immediately in front of the bases of the 3^rd dorsal elytral striae. These are distinct from stria in that they generally delimit the outer edge of a broad medial depression. The pronotal disk is elevated laterad the plica.

Elytra – Characters of the elytra mostly comprise the traditional configuration of a highly conserved system of longitudinal striae (see Fig. 1). Common modifications include abbreviation from either the anterior or posterior (basal or apical, respectively) ends, some variation in depth of impression, and rarely connection of one or more striae at their basal or apical ends. In a small number of species, primarily those we place in the Operclipygus marginellus group, the outer subhumeral stria is sub- or fully carinate, defining a lateral elytral border separating the dorsum from the epipleuron. Operclipygus species exhibit variation in the number of epipleural striae, which lie very close and parallel to the lateral elytral margin along the side of the body. Many descriptions include the number of ‘complete’ epipleural striae (see Fig. 2). In such cases an additional abbreviated stria may be present. The epipleural striae are always well separated and distinguishable from the subhumeral stria(e).

Other important characters of the elytra include various sculpturing of the disk, particularly along the apical margin. Some species and groups, especially the Operclipygus sejunctus group, exhibit disorganized punctures in the apical half of the elytron, generally increasing in density apically (Fig. 5F). In other groups, especially the Operclipygus impunctipennis group, there may be a well organized series of punctures along the apical margin (Fig. 5G), and in some these coalesce into a distinct stria (Fig. 5H).

Venter – The sterna and ventrites have numerous characters that vary among species and species groups. One of the most significant ventral character systems is the prosternal-mesoventral junction. Traditionally Exosternini as a whole have been defined by an emarginate prosternal base (e.g. Bickhardt 1917). This has been discussed and discredited (e.g. Wenzel 1976), primarily due to the full range of variation exhibited in Operclipygus, from a strongly produced prosternal keel to a strongly emarginate one. The breadth of the prosternum varies considerably in the genus, though this is difficult to describe. The carinal striae of the prosternum are almost invariably present and complete, but they vary somewhat in the angle of convergence and anterior or posterior connection. We refer in some descriptions to secondary striae, which are fine strioles occasionally present alongside the base of the primary carinal striae (Fig. 6A). The prosternal lobe varies in shape and development, as well as in the presence and completeness of its marginal stria, but these are relatively minor and only detailed in descriptions where particularly distinct.

Beyond the anterior shape of the mesoventrite, its major characters regard the presence of marginal and discal mesoventral striae. The marginal stria is usually present, and ranges from complete and distinct to broadly interrupted. Where interrupted it is often approached by what we term the mesometaventral stria. This latter stria has its apparently plesiomorphic position coincident with the mesometasternal suture. But in most Operclipygus, it is variably displaced anterad. The mesometaventral stria generally forms a continuous arch with the lateral metaventral stria (Fig. 6C). However, in a few taxa, particularly in the Operclipygus marginellus group, these are interrupted laterally, both terminating in a moderate to distinct depression at the inner edge of the mesocoxa.

The metaventrite exhibits a few useful characters of sculpture and striation. The most important and variable is completeness and position of the lateral metaventral stria. The commonest state is that it extends at a slight angle more or less straight and completely toward the inner anterior corner of the metacoxa, though it is commonly abbreviated apically. It may extend in a more lateral direction, toward the middle or outer corner of the metacoxa, in which case it is more often curved. Rarely it meets a recurrent stria, which recurves forward toward the metepisternum. A few species groups (especially Operclipygus sulcistrius and Operclipygus sejunctus groups) have a secondary lateral stria that parallels the primary metaventral stria along its outer edge for some or most of its length (Fig. 6C). A few species, primarily those in the Operclipygus sejunctus group, exhibit coarse punctures on the metaventrite (Fig. 6C). A small number of species show a dimorphism in which the meta- and mesoventrites are depressed and/or finely setose in the males (Fig. 19G).

The main characters of the abdominal ventrites are related to the lateral striae of the first visible ventrite (morphologically the 3^rd sternite), which run anteroposteriorly along the inner edge of the metacoxa. There may be one or two of these, termed the inner and outer, and they may be variably complete to obsolete. Frequently the outer stria is abruptly curved laterad behind the metacoxa. Essentially all Operclipygus exhibit a small gland opening near the posteromedial corner of the metacoxa (Fig. 34A), as do many other Exosternini. In some species, particularly in the Operclipygus impunctipennis group, this fovea is enlarged, sometimes greatly (Fig. 6D), and may also be displaced laterad, usually in association with a bent outer lateral abdominal stria. Otherwise few characters of the abdominal venter are used.

Pygidia – While technically part of the abdomen, the 6^th and 7^th abdominal tergites, termed the propygidium and pygidium, merit special discussion in any Histeridae. These are greatly varied in punctation in Operclipygus. Most importantly they frequently exhibit a very fine, dense ground punctation (Fig. 6E), against which background larger, coarser secondary punctures may be variously impressed. The propygidium rarely exhibits lateral striae, but is generally free of striae. The apical marginal stria/sulcus of the pygidium is, however, extremely varied and important for species recognition. It is completely absent in only very few species, particularly in the Operclipygus hospes group. In most species it is coarsely and completely impressed, with the depth, coarseness and completeness varied among species. The most remarkable modifications include foveate basal enlargements (Fig. 6E), which conceivably funtion as mycangia (Caterino and Tishechkin, pers. obs.). These are, however, found only in a few common species in the Operclipygus fossipygus group.

Legs – We utilize relatively few characters of the legs in the descriptions and keys in this paper. The tibiae are markedly expanded in a few species, providing useful characters, mainly within the Operclipygus marginellus group. The tarsi and their claws also provide valuable characters for distinguishing a couple species groups, especially in the arrangment of ventral setae, shape of the apical tarsomere, and shape of the claws. While there is considerable variation in marginal tibial dentation and spines, we have not found states that are sufficiently distinct to be useful for grouping or for species recognition, except in a few extreme cases.

Genitalia, male – Male genitalia, including the telescoping 8^th-10^th abdominal segments, are extremely useful for recognizing species and species groups, and are described and illustrated extensively throughout the paper (see Fig. 3 for terminology). Accessory sclerites at the base of the 8^th tergite (T8) were first noted in Exosternini by Kanaar (1997), who observed muscle attachment to them. These small sclerites are present in most, but not all Operclipygus. In a few cases, we must acknowledge that their absence may be artifactual, as they may become dissociated during dissection. However, they are consistently absent in a few subgroups of species. A new character which we utilize in descriptions relates to the position of the attachment line of the basal membrane of T8. The basal apodemes of this segment lie within the tube of the genitalia, while the distal portion of the tergite forms an external surface. How deeply embedded the apodemes are in the genital tube appears characteristic in many species. This depth is described in relation of the distinct membrane attachment line to the tergite's basal emargination. The ventrolateral apodemes of T8 fall into two distinct categories with respect to symmetry. In many species they project most deeply beneath near their bases, tapering toward the apex, while in others the apodemes project most deeply at their middles, tapering evenly basally and apically. The latter state is generally associated with an interruption of the apicolateral margin of the tergite, where the apodemes end, and an abrupt bend to the apex. This is further often associated with a distinct desclerotization near this bend, indicating flexibility of the dorsal apices.

The male 8^th sternite (S8) comprises two halves, usually divided along the midline, though they may be fused for some of that length. The sides of the sternites curve upward, usually curving over dorsally, forming a internally open troughs referred to as apical guides. These are quite varied in degree of dorsal enclosure, as well as in shape of the upper inner edge, and are described for most species. The apices of S8 generally bear some setae, though these may be difficult to see, and are not comprehensively described (or illustrated). In a few species the apices are divergent, and may be broadly membraneous, forming a velum, presumably used in maintaining hold and position on the female.

The male T9 and T10 are intimately associated, with the apices of T9 nearly enclosing T10 dorsally. T9 itself shows little variation among groups, with a couple notable exceptions: in the Operclipygus dubius group its apices are apparently rotated and expanded to form peculiar and varied distal flanges. Like S8, T9 usually comprises separate lateral halves, approximate near their bases. However, they may be fused at this point (again in most species of the highly apomorphic Operclipygus dubius group). T10 also comprises separate lateral halves in most species, though partial or complete fusion along the midline is observed in several taxa. The 9^th sternite (S9 - often referred to as the spiculum gastrale) forms an elongate guide that articulates at its apex with the aedeagus. Its shape varies considerably, in basal and apical width, as well as in the depth of emarginations at either end. We generally refer to everything basad the apical expansion as the stem, and the apical portion as the head. The distal margin of the head generally bears an upturned apical flange, which may be complete or interrupted, depending on the depth of the apical emargination. The sides of the head are also variously upturned.

The aedeagus itself comprises the basal piece, the tegmen, and the (internal) median lobe. The proportion of total length accounted for by the basal piece and the tegmen varies among species, less so among groups. The basal piece exhibits some variation in its apical shape, related to tegmen articulation, but we have not made extensive reference to this. The shape of the tegmen is quite variable, though it is most frequently simply narrowly tubular, narrowed and weakly downturned at the apex. Its most important character is the position, shape, and strength of what we term the medioventral process This is a usually dentiform process that may or may not be articulated with the ventrolateral membrane of the tegmen, projecting beneath the tegmen at some distance from its base. In most cases the shape of this process is described as seen in a dorsal view, visible through the body of the tegmen, though the degree of projection is best appreciated in lateral view. The median lobe consists of a pair of proximal apodemes and an apical gonopore. The proximal apodemes may be simple thin rods extending toward the base of the aedeagus, may be uniformly thickened, or are frequently differentiated, with the gonopore ends thicker, and the more proximal portion of the rods thin. The gonopore itself varies primarily in width relative to the tegmen width. The position of the gonopore relative to the apex of the tegmen is probably uninformative due to its presumed mobility for extrusion.

Genitalia, female – Female genitalia, characters of the ovipositor, spermathecae, and associated abdominal segments do show some variation, but mostly at higher, intergeneric levels, so beyond a general characterization of the genus (see description, below) we do not detail female genitalia in this paper. Further documentation of variation within Operclipygus may help to further refine intrageneric relationships and groupings.

Recognizing members of Operclipygus

Collectively diagnosing the group of related species that we assign to Operclipygus is challenging. No single distinctive character remains constant through the group, synapomorphic or otherwise. The presence of a marginal pygidial stria/sulcus is almost sufficient to place a specimen into Operclipygus; only a very small number of excluded species exhibit this character. A marginal pygidial stria is seen in most Mecistostethus, which have the body strongly depressed and dorsally setose (see Caterino et al. 2012). A few species in a couple of undescribed genera also have a pygidial stria but in one case the pygidium itself strongly prolonged and apically pointed; in another there are deep lateral mesoventral foveae and no sutural elytral stria. Otherwise, if a New World histerine specimen has a marginal pygidial stria, it is Operclipygus.

Much harder is placing those true Operclipygus that lack a pygidial stria into the genus. Most of the Operclipygus that lack this stria are in the Operclipygus impunctipennis group, most of which have very fine, dense pygidial ground punctation, a character sufficient to place a specimen in the genus. Others in this group have an apical marginal stria or puncture series on the elytron, also sufficient for placement. Several members of the Operclipygus hospes group lack a pygidial stria, but these can easily be recognized by their elongate, subdepressed body form and their two lateral striae on the 1^st abdominal ventrite. Finally a few members of the Operclipygus hamistrius group lack the pygidial stria, but all show conspicuous transverse microsculpture on the pygidium, and generally will have a broken and recurved anterior submarginal pronotal stria.

Taking a different perspective, it is more or less possible to diagnose some other groups of New World Exosternini that might otherwise be confused with Operclipygus:

Phelister sanguinipennis group: This is a relatively small group of species that often occur abundantly in flight intercept trap and carrion and dung pitfall trap samples in the neotropics. They may be similar to some species of Operclipygus, mainly in that they may have an outwardly arcuate anterior pronotal margin, median pronotal gland openings that are displaced posterad onto the pronotal disk, and an anterior submarginal pronotal stria which may be broken and recurved posterad for some distance. But preliminary analyses do not support a close relationship between the groups. Members of the Phelister sanguinipennis group may generally be separated from Operclipygus by the following characters: prescutellar impression usually elongate oval, about as long as scutellum; propygidium strongly transverse, often depressed at sides; pygidium relatively short, lacking marginal sulcus; prosternal keel relatively broad, carinal striae generally at least partly effaced; base of prosternal keel emarginate to truncate, never outwardly arcuate; pronotum with marginal stria usually complete across front, anterior submarginal stria rarely present; central portion of anterior pronotal margin often projecting; outer subhumeral elytral stria never complete (may be absent); inner subhumeral stria never present.

Phelister blairi group: This is a large group of mostly undescribed species that is destined to be removed from Phelister and probably split into multiple genera. The feature by which they most often may be confused with Operclipygus is the posteriorly displaced median pronotal gland openings. They may usually be separated from Operclipygus by the following characters: median pronotal gland openings distinctly annulate; prescutellar impression larger than scutellum, often much larger and semicircular; frons and epistoma narrowly and deeply impressed, the epistoma usually with subcarinate lateral ridges; prosternal keel usually emarginate at base.

Checklist of the species of Operclipygus

Operclipygus sulcistrius group

Operclipygus sulcistrius Marseul, 1870

Operclipygus schmidti sp. n.

Operclipygus lucanoides sp. n.

Operclipygus simplistrius sp. n.

Operclipygus mirabilis group

Operclipygus mirabilis (Wenzel & Dybas, 1941) comb. n.

Operclipygus pustulifer sp. n.

Operclipygus plaumanni sp. n.

Operclipygus sinuatus sp. n.

Operclipygus mutuca sp. n.

Operclipygus carinistrius (Lewis, 1908) comb. n.

Operclipygus parensis sp. n.

Operclipygus schlingeri sp. n.

Operclipygus kerga group

Operclipygus kerga (Marseul, 1870)

Operclipygus punctistrius sp. n.

Operclipygus planifrons sp. n.

Operclipygus conquisitus group

Operclipygus conquisitus (Lewis, 1902)

Operclipygus bicolor sp. n.

Operclipygus friburgius (Marseul, 1864)

Operclipygus impuncticollis group

Operclipygus impuncticollis (Hinton, 1935)

Operclipygus britannicus sp. n.

Operclipygus bickhardti sp. n.

Operclipygus panamensis group

Operclipygus panamensis (Wenzel & Dybas, 1941)

Operclipygus crenatus (Lewis, 1888)

Operclipygus sejunctus group

Operclipygus sejunctus (Schmidt, 1896) comb. n.

Operclipygus pecki sp. n.

Operclipygus juninensis sp. n.

Operclipygus depressus (Hinton, 1935)

Operclipygus setiventris sp. n.

Operclipygus itoupe sp. n.

Operclipygus punctiventer sp. n.

Operclipygus mortavis group

Operclipygus mortavis sp. n.

Operclipygus ecitonis sp. n.

Operclipygus paraguensis sp. n.

Operclipygus dytiscoides group

Operclipygus dytiscoides sp. n.

Operclipygus carinisternus sp. n.

Operclipygus quadratus sp. n.

Operclipygus crenulatus sp. n.

Operclipygus dubitabilis group

Operclipygus dubitabilis (Marseul, 1889)

Operclipygus yasuni sp. n.

Operclipygus impressifrons group

Operclipygus angulifer sp. n.

Operclipygus impressifrons sp. n.

Operclipygus dubius group

Operclipygus dubius (Lewis, 1888)

Operclipygus andinus sp. n.

Operclipygus intermissus sp. n.

Operclipygus variabilis sp. n.

Operclipygus validus sp. n.

Operclipygus lunulus sp. n.

Operclipygus remotus sp. n.

Operclipygus occultus sp. n.

Operclipygus perplexus sp. n.

Operclipygus extraneus sp. n.

Operclipygus hospes group

Operclipygus hospes (Lewis, 1902)

Operclipygus ignifer sp. n.

Operclipygus subterraneus sp. n.

Operclipygus callifrons sp. n.

Operclipygus colombicus sp. n.

Operclipygus incisus sp. n.

Operclipygus prominens sp. n.

Operclipygus tiputinus sp. n.

Operclipygus minutus sp. n.

Operclipygus inquilinus sp. n.

Operclipygus tenuis sp. n.

Operclipygus communis sp. n.

Operclipygus belemensis sp. n.

Operclipygus innocuus sp. n.

Operclipygus diffluens sp. n.

Operclipygus confluens sp. n.

Operclipygus fusistrius sp. n.

Operclipygus ibiscus sp. n.

Operclipygus novateutoniae sp. n.

Operclipygus gratus sp. n.

Operclipygus confertus sp. n.

Operclipygus rileyi sp. n.

Operclipygus assimilis sp. n.

Operclipygus praecinctus sp. n.

Operclipygus impositus sp. n.

Operclipygus curtistrius sp. n.

Operclipygus bulbistoma sp. n.

Operclipygus farctus group

Operclipygus farctus (Marseul, 1864)

Operclipygus bidessois (Marseul, 1889)

Operclipygus subrufus sp. n.

Operclipygus plicatus (Hinton, 1935) comb. n.

Operclipygus petrovi sp. n.

Operclipygus distinctus (Hinton, 1935)

Operclipygus atlanticus sp. n.

Operclipygus gilli sp. n.

Operclipygus proximus sp. n.

Operclipygus prolixus sp. n.

Operclipygus impressistrius sp. n.

Operclipygus farctissimus sp. n.

Operclipygus inflatus sp. n.

Operclipygus distractus (Schmidt, 1896) comb. n.

Operclipygus punctifrons sp. n.

Operclipygus latemarginatus (Bickhardt, 1920) comb. n.

Operclipygus hirsutipes group

Operclipygus hirsutipes sp. n.

Operclipygus guianensis sp. n.

Operclipygus hamistrius group

Operclipygus hamistrius (Schmidt, 1893) comb. n.

Operclipygus geometricus (Casey, 1893) comb. n.

Operclipygus rubidus (Hinton, 1935) comb. n.

Operclipygus quinquestriatus sp. n.

Operclipygus campbelli sp. n.

Operclipygus dybasi sp. n.

Operclipygus pichinchensis sp. n.

Operclipygus rufescens sp. n.

Operclipygus impressicollis sp. n.

Operclipygus nubosus sp. n.

Operclipygus arquus sp. n.

Operclipygus propinquus sp. n.

Operclipygus intersectus sp. n.

Operclipygus troglodytes sp. n.

Operclipygus chiapensis sp. n.

Operclipygus montanus sp. n.

Operclipygus plicicollis group

Operclipygus plicicollis (Schmidt, 1893)

Operclipygus cephalicus sp. n.

Operclipygus longidens sp. n.

Operclipygus fossipygus group

Operclipygus fossipygus (Wenzel, 1944)

Operclipygus foveipygus (Bickhardt, 1918)

Operclipygus gibbulus (Schmidt, 1889) comb. n.

Operclipygus fungicolus (Wenzel & Dybas, 1941)

Operclipygus subdepressus (Schmidt, 1889)

Operclipygus simplicipygus sp. n.

Operclipygus therondi Wenzel, 1976

Operclipygus disconnectus sp. n.

Operclipygus olivensis sp. n.

Operclipygus impunctipennis group

Operclipygus impunctipennis (Hinton, 1935) comb. n.

Operclipygus punctissipygus sp. n.

Operclipygus granulipectus sp. n.

Operclipygus pauperculus sp. n.

Operclipygus nicodemus sp. n.

Operclipygus tripartitus sp. n.

Operclipygus latifoveatus sp. n.

Operclipygus lissipygus sp. n.

Operclipygus mangiferus sp. n.

Operclipygus foveiventris sp. n.

Operclipygus marginipennis sp. n.

Operclipygus maesi sp. n.

Operclipygus pacificus sp. n.

Operclipygus nitidus sp. n.

Operclipygus subviridis sp. n.

Operclipygus vorax sp. n.

Operclipygus chamelensis sp. n.

Operclipygus marginellus group

Operclipygus marginellus (J.E. LeConte, 1860) comb. n.

Operclipygus striatellus (Fall, 1917) comb. n.

Operclipygus formicatus sp. n.

Operclipygus hintoni sp. n.

Operclipygus orchidophilus sp. n.

Operclipygus baylessae sp. n.

Operclipygus selvorum sp. n.

Operclipygus dentatus sp. n.

Operclipygus ashei sp. n.

Operclipygus incertae sedis

Operclipygus teapensis (Marseul, 1853) comb. n.

Operclipygus punctulatus sp. n.

Operclipygus lama Mazur, 1988

Operclipygus florifaunensis sp. n.

Operclipygus bosquesecus sp. n.

Operclipygus arnaudi Dégallier, 1982

Operclipygus subsphaericus sp. n.

Operclipygus latipygus sp. n.

Operclipygus elongatus sp. n.

Operclipygus rupicolus sp. n.

Operclipygus punctipleurus sp. n.

Operclipygus falini sp. n.

Operclipygus peregrinus sp. n.

Operclipygus brooksi sp. n.

Operclipygus profundipygus sp. n.

Operclipygus punctatissimus sp. n.

Operclipygus cavisternus sp. n.

Operclipygus siluriformis sp. n.

Operclipygus parallelus sp. n.

Operclipygus abbreviatus sp. n.

Operclipygus pygidialis (Lewis, 1908)

Operclipygus faltistrius sp. n.

Operclipygus limonensis sp. n.

Operclipygus wenzeli sp. n.

Operclipygus iheringi (Bickhardt, 1917)

Operclipygus angustisternus (Wenzel, 1944)

Operclipygus shorti sp. n.