Pachybrachis (Coleoptera, Chrysomelidae, Cryptocephalinae) of Eastern Canada

Abstract Seventeen Pachybrachis species occurring in eastern Canada [Ontario (ON), Québec (QC), New Brunswick (NB), Nova Scotia (NS), and Prince Edward Island (PE)] are treated by the authors. Two new national records were discovered, both from southernmost Ontario: P. cephalicus Fall and P. luctuosus Suffrian. Four species were new provincial records: P. cephalicus (ON), P. luctuosus (ON, QC), P. obsoletus Suffrian (NB), P. peccans (PE). A fully illustrated key to the Pachybrachis of eastern Canada is provided and supported with extensive photographs, distribution maps, and plant associations. Three species were distributed from southern Ontario into at least one province in the Maritimes (P. nigricornis (Say), P. obsoletus Suffrianand P. peccans Suffrian). Six species were distributed along the shores of the Great Lakes (Erie, Michigan, and Ontario) and rivers (Ottawa, Saguenay and St. Lawrence), but unknown from central and northern ON and QC (P. bivittatus (Say), P. hepaticus hepaticus (F. E. Melsheimer), P. othonus othonus (Say), P. pectoralis (F. E. Melsheimer), P. spumarius Suffrianand P. trinotatus (F. E. Melsheimer)). Seven species were rare, five being found exclusively from southern ON (P. calcaratus Fall, P. cephalicus, P. luridus (Fabricius), P. subfasciatus (J. E. LeConte)and P. tridens (F. E. Melsheimer)), with two having, in addition, a disjunct population in QC (P. atomarius (F. E. Melsheimer)and P. luctuosus). One species was found to be the northern most extension of an eastern United States (US) distribution into the eastern townships of QC (P. m-nigrum (F. E. Melsheimer)). There were no Pachybrachis that could be considered arctic, subarctic, or boreal species; no specimens were found from Labrador and Newfoundland, and all species had southern affinities. Pachybrachis atomarius, P. calcaratus, P. luridus, P. subfaciatus, and P. tridens, not seen over the last 30–70 years, may be extirpated from eastern Canada.

praeclarus as a replacement name for P. elegans Blatchley, 1910, since this name was already preoccupied by a Pachybrachis species described by Graëlls (1851) from Spain. Evans (1895a, b) listed several beetle species collected in the district of Sudbury (ON), including P. femoratus (= P. luridus?) and P. infaustus (= P. atomarius); however, voucher specimens were not found for this study. In a series of papers on the Chrysomelidae of Ontario and Québec, Wickham (1896) provided a key to nine species of Pachybrachis, plus a description and illustration of beetles reported to be P. viduatus, but that in actuality were clearly P. bivittatus.
In his report on the insects of the Toronto region (ON), Walker (1913) listed P. atomarius, P. femoratus (= P. luridus?), P. hepaticus, P. othonus and P. trinotatus. Gibson (1915Gibson ( , 1919 reported several collection records of Pachybrachis in his reports to the Entomological Society of Ontario, but they were all from Manitoba. During the same period, H. C. Fall (1915) thoroughly revised the Nearctic Pachybrachis (Pachybrachys), and his revision is still, today, the only available complete taxonomic work on this genus. Out of the 159 recognized species, only six were given with a distribution extending into eastern Canada: luridus (ON), othonus othonus (MB, ON), peccans (MB, NB, ON), relictus (ON), subfasciatus (ON), and trinotatus (ON), with calcaratus located in nearby Detroit (USA, Michigan). The well-known Catalogue of the Coleoptera of America, north of Mexico of Leng (1920) relisted the species treated by Fall (1915), but the distributions were reduced to a few state records or short statements, with the result that only P. peccans was clearly reported from New Brunswick. No relevant information on Pachybrachis was added in the supplements, except the record of P. donneri from Oregon Mutchler 1927, 1933;Blackwelder 1939;Blackwelder and Blackwelder 1948).
In the thirties, Chagnon published a series of contributions on the most important beetles of the province of Québec in the journal Le Naturaliste canadien (Chagnon 1933(Chagnon -1939. The Cryptocephalini were treated in 1937 (Chagnon 1937). Four species of Pachybrachis were keyed out (P. bivittatus, P. carbonarius (= P. nigricornis), P. othonus and P. trinotatus), and an additional four only mentioned (P. atomarius, P. femoratus (= P. luridus), P. peccans, P. relictus Fall). The year after, Chagnon (1940) grouped together his previous contributions and published them as a separate book. The brother Adrien Robert of the Université de Montréal updated the nomenclature used in the book of Chagnon (1940), but did not otherwise modify its contents (Chagnon and Robert 1962), except that a table was added at the end of the book, giving both the nomenclature used by Chagnon (1940) and the more recent nomenclature. As regards Pachybrachis, no changes were noted between the two editions.
The list of Coleoptera collected by Notman (1919) at Cochrane in northern Ontario did not include Pachybrachis.
Father Léopold (1934) of the entomology laboratory at the agriculture institute of Oka (QC) published a list of beetles preserved in the collection of the institution. Seven species of Pachybrachis were listed, five of which are still valid: P. atomarius, P. difficilis (= P. nigricornis), P. hepaticus, P. peccans, and P. tridens. His P. pubescens (= P. morosus) and P. vestigialis were very likely misidentified. Hicks (1944Hicks ( , 1945Hicks ( , 1947a collected mainly in southern Ontario and provided several new province records or information on the host plants or biology of species. He reported that P. calcaratus, P. peccans, P. othonus and P. relictus were taken by sweeping the vegetation, and P. obsoletus was observed on willows (Salix sp.). Latendresse (1963) increased to 36 the number of known chrysomelid species from the Saguenay region on the north shore of the St. Lawrence, in Québec. A century before, Saunders (1868) had found only two species of leaf beetles, but neither collector found Pachybrachis species in their survey. Balsbaugh (1973) studied the geographical variation in Pachybrachis othonus, recognized three subspecies, and described P. othonus sioux Balsbaugh as a new subspecies. The geographical variation of P. nigricornis was treated three years later (Balsbaugh and Tucker 1976), but the distribution of subspecies needs to be clarified in eastern Canada since three have been reported for this region .
The Checklist of Chrysomelidae of Canada, United States, Mexico, Central America and the West Indies of Wilcox (1975) was a working draft which was pretty complete taxonomically, but lacked detailed information on the distribution of species. LeSage (1991) provided the known distribution in Alaska and in Canada by province for all chrysomelid species, including Pachybrachis. Laplante et al. (1991) extracted the information for Québec only, and published it as a separate checklist for this province. Lawson (1976) described and illustrated the structural details of the egg and larval case of P. bivittatus. The mature larva of the same species was sketched by Lawson (1991), andLeSage (1985) described and illustrated all its larval instars and egg. This author also treated in detail these life stages for P. peccans. Eggs were distinguished by their external ornamentation, the larval instars by their size and by their head and leg chaetotaxy.
Edward G. Riley, Shawn M. Clark, R. Wills Flowers and Arthur J. Gilbert are the authors of the most recent synthesis on American Chrysomelidae (Riley et al. 2002). The reader is referred to this major work for diagnoses and keys to subfamilies, tribes and genera. The North American Pachybrachis species have not been assigned to subgenera as the Palaearctic species were in the recent Catalogue of Palaearctic Coleoptera (Schöller et al. 2010).
The Catalogue of the Leaf Beetles of America North of Mexico by Riley et al. (2003) was the first extensive and complete catalogue ever published on this family of beetles for the North American continent north of Mexico. Consequently, we have followed the nomenclature and classification adopted by these authors. The compiling by Clark et al. (2004) of the known host plants of the Nearctic Pachybrachis is the best and most extensive source of information available on the subject. Both works are essential tools to anybody interested in Pachybrachis species and Nearctic leaf beetles in general.
An examination of leaf beetle specimens in the largest beetle collections in Kentucky, inventory work in state nature preserves and other protected areas, and a review of the literature revealed 20 species of Pachybrachis present in Kentucky, 14 of which were new state records . Twenty species of Pachybrachis were also reported for Illinois (Barney 1984).
The latest contribution on the eastern Canadian Pachybrachis is by Webster et al. (2012), based on extensive collecting of beetles in New Brunswick by the senior author. Pachybrachis bivittatus and P. m-nigrum were added to the previously known P. peccans and P. pectoralis for this province.

Provinces
For the purposes of this study, eastern Canada is defined as provinces east of Manitoba: Ontario (ON), Québec (QC), New Brunswick (NB), Nova Scotia (NS), Prince Edward Island (PE), Newfoundland (NF) and Labrador (LB). When not given on labels, counties were found using the gazetteer of CPCGN (1974CPCGN ( , 1988 for Ontario, CTQ (1987) for Québec, CPCGN (1994a) for New Brunswick, CPCGN (1993) for Nova Scotia, and CPCGN (1994b) for Prince Edward Island. No specimens were available from Labrador and Newfoundland. In older specimens, for example those collected by Brimley in Prince Edward and Hasting Counties, only the county names were given in the collection data.

Species data
For each species of Pachybrachis found in eastern Canada, the following information is provided: name, synonymies, habitus photo, brief description of species recognition characters, distribution and maps, label data, recorded or potential host plants, and comments.

Label data
For each specimen examined the following information is provided: province, county/ district, date, label information that may include potential host plants, habitat or collection method, collector, number of males and females, and museum. If a specimen had a H. C. Fall identification label or was found in Fall's personal collection (Fall-MCZ), this information was cited before the museum name. Within a species treatment, data are ordered alphabetically by province, county/district, locale, and then date.

Sex determination
Determination of sex is relatively easy as follows: males ( Figure 9a) are generally smaller and less robust than females, with the abdomen flat and more or less concave; in females ( Figure 9b) the abdomen is convex beneath, the last segment with a deeply rounded fovea (depression). Singleton females of many species cannot be confidently identified without associated males for dissection.

Size measurement
Ten males (when available) of each species were measured using a Leica Z16 APO microscope equipped with a DFC295 digital color camera and Leica Application Suite software.
There are many species of Pachybrachis in the eastern US and Canada that could only be confidently separated and identified via examination of the male reproductive organ (aedeagus). This was accomplished by removing the labels from a pinned (and usually pointed) specimen and placing the pointed, pinned specimen in gently boiling water for one minute. The now relaxed pinned (or separated) beetle was placed in a Petri dish with a small amount of 70% Ethanol. The beetle was held upside down with featherweight forceps and the abdomen pried off with an insect pin. The abdomen was then held by the pygidium with a pin and the aedeagus removed with fine forceps. After drying, the beetle was reattached to a new point using clear nail polish, as were the abdomen and aedeagus.

Physiographic features
The Carolinian Life Zone is by far the richest zone for the Pachybrachis fauna of eastern Canada, several species being exclusively associated to it (e.  (Fox and Soper 1952, 1953, 1954Shelford 1963;Hosie 1979;Johnson 2012).
The major rivers seem to play an important role in the distribution of some species. For example, P. bivittatus [Map 2] is closely spread along the Great-Lakes-St. Lawrence River system and in the Ottawa River valley. The Saguenay River seems a northern limit impassable for all species.
There are two noticeable disjunct refugia. The most important is the well-known Eardley Escarpment located on the south border of Gatineau Park. It corresponds to about 40 km of steep cliffs oriented southwards which are significantly warmer than the Ottawa Valley below and the Laurentian Highlands above. Eastern red cedar (Juniperus virginiana L.) is well represented on the cliffs, and the relatively recent discovery of its associated olive hairstreak, Callophrys grynea (Hubner), has been an enthusiastically received discovery for butterfly collectors (Hall 1991, NCC 2011a. There are over thirty additional vascular plant species growing exclusively there at their northernmost limits, considerably disjunct from their main distribution south of the Great Lakes (Brunton and Lafontaine 1971).
The second refugium corresponds to a small zone between the islands Île-aux-Allumettes and Île-du-Grand-Calumet, both in Pontiac County (QC), within the Ottawa River. A special flora has been identified there by botanists, but no results were published. On the other hand, Desroches and Laparé (2004) reported the first captures of the ribbonsnake (Thamnophis sauritus septentrionalis Rossman) in this refugium. The distribution of P. luctuosus corresponds to this pattern [Map 6].
Finally, the influence of Lake Champlain cannot be ignored. Although almost completely lying in the states of Vermont and New York in the United States, it extends about 10 km across the Canadian border. Its microclimate is important enough to allow some plants and animals to cross the border and reach their northernmost limits in the southeastern townships of Québec (DECNY 2012). The very recent discovery of two sycamores (Platanus occidentalis L.) in this region -a first record for Québec -is a good exemple of such distribution (Bibeau-Lemieux 2010.

Codens of collections examined and referred to in this study are as follow:
The major insect collections (and curators) in eastern Canada and the United States, which contained Pachybrachis specimens from eastern Canada, are listed below: Remarks. There has been some debate as to the correct spelling of the genus Pachybrachis. Fall's (1915) monumental work used Pachybrachys Chevrolat and cited its general American usage by J. L. LeConte. However, this emendation was unjustified under the rules of the International Code of Zoological Nomenclature (ICZN 1999, Article 32).
Pachybrachis is a member of the subfamily Cryptocephalinae Gyllenhall, 1813, commonly known as the case bearers due to the fact that all known larval stages live in a case constructed of their fecal matter and often plant debris (LeSage 1985). Their cylindrical, compact body characterizes the adults, which usually have the head retracted into the pronotum to the level of the eyes.
In the recent revision of family-group names in Coleoptera (Bouchard et al. 2011), the former tribe Pachybrachini Chapuis, 1874 was relegated to subtribe under the tribe Cryptocephalini Gyllenhal, 1813. Pachybrachina Chapuis, 1874 contains only two genera north of Mexico, Griburius and Pachybrachis, and is characterized by long filiform antennae, with a marginal bead at the base of pronotum which is not crenulate. Riley et al. (2002) separated the two genera by prosternal charateristics (prosternum broad, as wide as long in Griburius, narrower, longer than wide in Pachybrachis). Additional generic keys can be found in Blatchley (1910), Chagnon and Robert (1962), Downie andArnett (1996), andCiegler (2007).
Useful morphological characters. Fall (1915) provided a very detailed "Review of Structural Characters Useful in Taxonomy," which we will not repeat here. However, there are a few key characters that will be useful to separate the seventeen Canadian species. These features will be described, detailed and illustrated, most of them being used in the identification key.
Size. The seventeen species can generally be divided into four size classes by average length: very small, <1.75 mm; small, >1.75 mm to 2.35 mm; medium, >2.35 mm to 2.85 mm; and large, >2.85 mm to 3.30 mm. Pachybrachis hepaticus is the only species in the very small category, with a mean length of 1.68 mm. Pachybrachis m-nigrum (2.59 mm), P. othonus othonus (2.63 mm), and P. luridus (2.65 mm) are in the medium category. Pachybrachis trinotatus (3.09 mm) and P. bivittatus (3.12 mm) are the only species with males averaging over 3 mm in length. Small is the largest category, with the remaining eleven species. Mean length and width of males are reported for each species. Females are generally larger, thus accounting for the larger overall sizes reported by Fall (1915).
Antennae. In most species (e.g. P. atomarius, Habitus 1; P. bivittatus, Habitus 2), the length of antennae equals about 2/3 to 3/4 the length of the body. There are two noticeable exceptions. In P. hepaticus (Habitus 5) the antennae do not exceed half of the body length, whereas in P. trinotatus (Habitus 17) the antennae equal or exceed the body length. Eyes. The eyes of P. pectoralis are close to each other and separated by less than their width ( Figure 1a). In most species the distance between the eyes roughly corresponds to their width (e.g. P. peccans, Figure 1b). A normal distance between eyes, coupled with the head coloration, can be diagnostic, as in P. atomarius that has a largely yellow face ( Figure 1c). In P. hepaticus, the eyes are very small and markedly remote, separated by much more than their diameter ( Figure 1d). Ocular lines. Many Pachybrachis species have an impressed line, called the ocular line, around the margin of the eyes, and in some species the line diverges from each eye as lines of darker colored punctures between the eyes (e.g. P. peccans, Figure 2a). This character is very consistent within each species, and it is easy to see provided the specimens are properly oriented and lighted. In P. hepaticus the ocular lines are very short but distinct above the eyes (Figure 2b). In other species, however, such ocular lines are absent (e.g. P. spumarius, Figure 2c). a b Figure 3. Front femora: a not enlarged, P. hepaticus b thickened, P. peccans.
Femora. Except for P. hepaticus (Figure 3a), the femora on the forelegs of all species ( Figure 3b) are incrassate or thickened in relation to the other femora. This character is difficult to see because in most cases legs are folded and pressed tightly against the body. Consequently, it might be necessary to relax the legs and spread them out to compare the front femora with those of the middle and hind legs. When such preparation is achieved, the larger size of the femora becomes evident (e.g. P. calcaratus, Habitus 3). Tibial spurs. In P. atomarius (Habitus 1), P. m-nigrum (Habitus 8), and P. trinotatus (Habitus 17), there is no apical spur on front tibia (Figure 5a), but a tuft of large apical setae grouped together may superficially look like a spur. In P. spumarius (Figure 5b, Habitus 14) the front tibial spur is very small, hidden and difficult to see, but the very large and exposed front tibial spur is unique and distinctive of P. calcaratus (Figure 5c, Habitus 3). In all species, except P. hepaticus, the middle tibiae are armed with small slender apical spur ( Figure 5d). In all species studied here, the hind tibiae are unarmed. Pronotum. In Pachybrachis, the pronotum is margined at base, the margin usually ornamented with a row of large punctures ( Figure 6a, close up). This character is very useful to separate Pachybrachis Chevrolat from Cryptocephalus Geoffroy or Bassareus Haldeman. The last two genera superficially look like Pachybrachis but are not margined at the base of the pronotum.
The density and pattern of pronotal punctures can be a useful character. Punctures usually dissipate near the side margins, and are generally a darker color than the background.
The pronotal coloration varies from a common mottled pattern (e.g. P. spumarius, Figure 6b), to a black M-mark on a light background (e.g. P. m-nigrum, Figure 6c), to an almost entirely black pronotum with only yellow basal and lateral markings (e.g. P. nigricornis carbonarius, Figure 6d). Elytra. As on the pronotum, the density and pattern of punctures on the elytra are easily seen and useful characters. The elytral punctures generally form fairly regular deep striae, consisting of one sutural, one marginal and eight discal striae on each elytron, although the first may be somewhat irregular in the basal third (e.g. P. luctuosus, Figure 7a). Punctures may be confused in the basal half but with a tendency towards regular rows in the apical half, as in P. calcaratus (Figure 7b).
Finally, punctures may be completely confused and not aligned at all in rows (e.g. P. hepaticus, Figure 7c).
The elytral color pattern is, of course, a very useful character for the identification of many species. The mottled pattern is common (e.g. P. spumarius, Figure 7d). Some species are vittate (= with longitudinal black stripes), sometimes with a lateral vitta interrupted as in P. bivittatus (Figure 7e). In some species, the elytra are largely black with only a few yellow markings or with narrow apical and lateral margins (e.g. P. nigricornis carbonarius, Figure 7f), or the elytra can be entirely black (e.g. P. luridus, Figure 7g). Pygidium. The coloration of the pygidium can be largely yellow (e.g. P. bivittatus, Figure 8a), dark with distinct yellow spots of various sizes (e.g. P. cephalicus, Figure  8b), or dark with faint small reddish spots (e.g. P. spumarius, Figure 8c). A completely black pygidium is distinctive of P. atomarius (Figure 8d). Sexes. Males are usually smaller and less robust than females, with their abdomen flat ( Figure 9a). In females, the abdomen is convex beneath, the last visible segment having a deep, round, concave depression or fovea (Figure 9b). Genitalia. In most cases, individuals of each sex can be identified to species using coloration and external morphological features alone. However, an examination of the aedeagus is essential for the determination of superficially similar and variable species, such as P. cephalicus, luctuosus and spumarius.
In Pachybrachis, the basal portion of the aedeagus may appear bulbous (e.g. P. luctuosus, Figure 10a) or more tubular (Figure 10b), but we don't know yet if this character is reliable and consistent. The apical half is usually considerably bent, sometimes at a right angle, the degree of the curvature being an important diagnostic feature. In lateral view, the tip of the aedeagus may appear straight, sinuous and curved upwards, or sinuous and curved downwards (e.g. P. spumarius, Figure 10b). In dorsal view, the tip offers various shapes: small, large, pointed, triangular, lanceolate, nipple-shaped (e.g. P. spumarius, Figure 10c), etc.
Although the genitalic features are very constant and most reliable, they have been rarely described and illustrated in Pachybrachis. In the following key to the males of the 17 species treated here, the aedeagus is reported for only three species when external morphological characters may not be sufficient. The female genitalia are still unknown for all of them.
Illustrated key to males Elytra mottled (Fig. 6.ii), spotted ( Fig. 16.iii), or mostly to entirely black ( Fig. 6.iv)  Many elytral punctures arranged in rows (Fig. 7.i); pronotum not reddish, rather yellow with black markings of various sizes and shapes (Fig. 7.ii)  Pronotum mottled (Fig. 9.i) or with reddish spots (Fig. 9.ii); elytra variable, black ( Fig. 9.iii) to mottled ( Fig. 9.iv)  Antennae shorter than body; pronotum black ( Fig. 11.i), mottled (Fig.11. ii), or with M-shaped marking (Fig. 11 14a Front tibia with large, curved spur ( Fig. 14.i, Habitus 3) ...... calcaratus Fall 14b Front tibia with tiny spur (Fig. 14.ii), or without spur (Fig. 14.iii)  Face largely dark (Fig. 15.ii); pygidium spotted, with spots of some specimens being smaller and fainter than illustrated (Fig. 15.iv)  Recognition. Body largely fuscous, dull, mottled with many yellow spots (Habitus 1); elytral puncturation dense, confused discally, more or less arranged in rows towards rear and sides; face of males predominately yellow; pygidium entirely black, convex ( Figure 8d); male size small: length 1.85 + 0.07 mm, width 1.01 + 0.03 mm. Distribution. The distribution in eastern Canada is restricted in southern Ontario to remnants of the Carolinian forest (Johnson 2012;Shelford 1963). In Québec, the distribution is isolated from the main distribution area (Map 1). The unique speci-men available was probably collected on the Eardley Escarpment, which is a warmer refugium created by cliffs of the Laurentian Highlands oriented southwards (Brunton and Lafontaine 1971   did not report any either. Clark et al. (2004) presents the known literature, but since adults were usually swept from vegetation, these records cannot automatically be interpreted as real host associations.
Comments. Pachybrachis atomarius is one of Fall's (1915) Group C species that have "great variation in the degree of (elytral) maculation." In spite of the extremely variable elytral mottling, ranging from heavily speckled with yellow to almost entirely black, P. atomarius males are relatively easy to identify by the combination of the predominately yellow face (Figure 1c) and entirely black, convex pygidium (Figure 8d). The entirely black, convex pygidium character also permits identification of singleton females.
Although P. atomarius is a typical eastern North American species distributed from Manitoba to Oklahoma to Atlantic states LeSage 1991;Barney, unpublished data), in Ontario it is restricted to the Carolinian Zone in the southernmost part of the province. Its presence in Québec is considerably disjunct from its main distribution area, and this isolation is due to the warmer microhabitat of the Laurentian Highlands cliffs of Eardley Escarpment, which are fully exposed southwards and harbor similarly disjunct insects and plants (Hall 1991;Layberry et al. 1998;NCC 2011a).
Since P. atomarius has not been collected in eastern Canada over the last 50 years, it is likely extirpated from the eastern Canadian fauna. ( Recognition. Body very large, primarily yellow (Habitus 2); prothorax suffused with rufous; elytral punctation confused, with somewhat apparent rows on disc; elytral color pattern bivittate, with outer vitta rarely entire (Figure 7e); pygidium yellow ( Figure  Pachybrachis calcaratus Fall, 1915 Host plants. Cinquefoil (Potentilla sp.) and strawberry (Fragaria sp.) (both Rosaceae) are the first host associations reported for P. cephalicus. The specimens were swept from these two plants growing in a sandy clearing within a dry oak-pine forest (LeSage, personal field notes). Since 1984, the previous Walsingham Forestry Station is part of the St. Williams Dwarf Oak Forest, the largest block of publicly owned forest in the Carolinian Life Zone (NHIC 1998).

Pachybrachis bivittatus
Comments. Pachybrachis cephalicus is another of Fall's (1915) Group C species that have "great variation in the degree of (elytral) maculation." The fairly large number of examined specimens may be misleading since they all come from only one event. In fact, P. cephalicus is very rarely collected in eastern Canada and known from only one locality within the Carolinian Life Zone. This is also a first record of this species for Canada. Recognition. Front femora not enlarged in comparison to those of middle and hind legs ( Figure 3a); eyes small and remote ( Figure 1d); antennae short, less than half body length (Habitus 5); integument densely, diffusely punctate ( Figure 7c); elytra tapered to apex; male size very small: length 1.68 + 0.07 mm, width 0.96 + 0.07 mm.
Host plants. No plant association records were available from specimens examined. Pachybrachis hepaticus hepaticus may be a polyphagous species, considering the number of plant families listed in Clark et al. (2004): Asteraceae, Euphorbiaceae, Fabaceae, Juncaceae, Salicaceae, and Tamaricaceae.
Comments. Of all the species here studied, the shortest antennae (Habitus 5) and smallest eyes are found in P. hepaticus hepaticus. Further investigation may require that a new genus is established for the eastern and western subspecies of hepaticus. Fall (1915) cited specimens from Montréal, May 24 (Liebeck Coll.); Toronto (Crew); and Scotia Junction, July 27 (Wenzel), but these specimens could not be located and examined. Recognition. Color black or piceous; ocular lines absent; pronotum and sides of elytra with few yellow marks; elytral punctures confused in scutellar area, in fairly regular rows in apical half; elytral striae deep and quite regular (Habitus 6); aedeagus with terminal nodule and denticle forming small, 90 o diamond shape ( Figure 10a); male size small: length 1.87 + 0.10 mm, width 0.95 + 0.11 mm. Distribution. A relatively rare Atlantic species distributed from Alabama to New York in the United States Barney, unpublished data). The Parry Sound specimens in Ontario and those of the Île-du-Grand-Calumet in the Ottawa River are two small populations disjunct from the main Atlantic one (Map 6).
Comments. Pachybrachis luctuosus is another of Fall's (1915) Group C species that have "great variation in the degree of (elytral) maculation." Fall commented that he would not be surprised if P. carolinensis Fall was a paler form of P. luctuosus. Our comparison of aedeagi of specimens identified by Fall as either luctuosus or carolinensis revealed the same, distinctive form -the subplanar surface with one median subapical denticle. Pachybrachis carolinensis appears to be a larger, more yellow variation, but more work needs to be done. P. luctuosus is reported for the first time in Canada, and therefore, is also a first record for ON and QC.    Blatchley, 1910:1130. Pachybrachys luridus var. festivus Fall, 1915 Recognition. Body dull black, densely, coarsely punctured; pronotum black with anterior median line and sides red or reddish yellow, varying to almost entirely red; elytra mottled with yellow, especially toward sides, varying to entirely yellow to entirely black (Habitus 7); front claws of male much enlarged (as in Figure 4a); male size medium: length 2.65 + 0.23 mm, width 1.45 + 0.12 mm.

Pachybrachis luridus (Fabricius
Distribution. Occuring in the eastern half of the United States   [2♀,ROM]; Can., G. M. Greene [1♂,USNM]. Host plants. No plant association records were available from Canadian specimens. In the United States, the false indigos (Baptisia leucantha T. & G., B. tinctoria (L.) R. Br.) (Fabaceae) were the associations most often cited by authors (Frost 1945, details in Clark et al. 2004). However, these plants are not present in Québec (Marie-Victorin 1995), and extremely rare in southern Ontario (Scoggan 1978).  stated that recently collected specimens in Kentucky were probably from oak (Quercus spp., Fagaceae).
Comments. Fall (1915) observed specimens from Ontario: Toronto (Wickham). However, no specimens of P. luridus have been collected from the province in the last 68 years, and one of its potential hosts (Baptisia spp.) were always extremely rare in southern Ontario (Scoggan 1978). Consequently, P. luridus is likely extirpated from the eastern Canadian fauna.  Recognition. Pronotum usually with thick, black, M-shaped marking; elytra yellow with variable black markings, but these usually leaving basal, lateral and sutural margins yellow, in addition to a basal and median yellow spots on each elytron (Habitus 8); male size medium: length 2.59 + 0.11 mm, width 1.42 + 0.07 mm.
Distribution. A typical eastern species distributed in the eastern half of the United States . Its presence in the south of the eastern Townships, in Québec, corresponds to the northernmost limit of this species (Map 8).
Comments. Balsbaugh and Tucker (1976) and Riley et al. (2003) recognized P. nigricornis as having four subspecies in North America. Fall (1915) described P. autolycus as a separate species with two "varieties," and he added the variety janus to P. carbonarius, which he also recognized as a separate species. Specimens from each of the provinces of NB, ON and QC included an assortment of var. carbonarius, var. difficilis, and the yellow variation of carbonarius as per Barney and Hall (2009). In the "Material examined" section above, the QC specimens from Fall's personal collection (Fall-MCZ) are listed, with an indication of his identification label of autolycus, var. difficillis. Recognition. Background color yellow, with numerous, usually not sharply outlined black spots on both pronotum and elytra (Habitus 10); eyes distant; ocular lines faint; male size small: length 1.87 + 0.16 mm, width 0.98 + 0.08 mm.

Pachybrachis obsoletus
Distribution. Species broadly distributed from North Dakota to New Mexico to Atlantic Coast in the United States , and in Canada from British Columbia to New Brunswick. In eastern Canada, it is found in Ontario, Québec and New Brunswick (Map 10).
Host plants. Pachybrachis obsoletus may be associated with peat bogs in eastern Canada. Specimens were collected in Alfred Bog (Pope 2011), andMer Bleue (NCC 2011b;Wikipedia 2011), two well-known bogs of Ontario. The Lanoraie specimens, in Québec, were collected in an ecological preserve, which includes several fens and bogs (MDDEP 2011). Larochelle specimens, also from Québec, had a wide range of potential plant associations. Leather leaf (Cassandra calyculata (L.) D. Don.) (Ericaceae) is definitively a host (LeSage, collecting and personal observations), whereas the beetles' presence on white pine (Pinus strobus) (Pinaceae) is very likely incidental. Sweeping from willows (Salix spp.) (Salicaceae) was reported by . Additionally, P. obsoletus was reported as causing light injury to cultivated roses in Saskatoon, Saskatchewan, but the species identification cannot be confirmed (Arnason 1942(Arnason , 1943Arnason et al. 1946;King et al. 1944King et al. , 1945Campbell et al. 1989).
Comments. Pachybrachis obsoletus has a broad distribution from Manitoba to Oklahoma and eastwards to the Atlantic Ocean, with Alberta and British Columbia disjunct from this main area  Recognition. Body robust. Pronotum black, with all margins and narrow median anterior stripe yellow; each elytron black, with rather narrow sub sutural, discal and marginal vittae yellow; legs yellow. Punctures of pronotum larger and denser than those on elytra; elytral punctures in somewhat regular rows on disc and sides (Habitus 11); male size medium: length 2.63 + 0.12 mm, width 1.56 + 0.09 mm.
Distribution. A typical eastern species distributed from North Dakota to Texas to the Atlantic Coast in the United States , and in the south of Ontario and Québec in eastern Canada (Map 11 Comments. Pachybrachis subfasciatus is another possible example of a species once living in the Carolinian Zone which may have been extirpated from the Canadian fauna. No specimens were collected in the last 55 years. If its association with black walnut is correct, this may explain its rarity, or even extinction, since Fox and Soper (1953) reported this tree occurring naturally only in rich woods in southernmost Ontario and considered recent trees above these limits to have been planted. species of the genus (Habitus 17). It is widely distributed in southern Ontario but is found only in the Ottawa River Valley and south of the eastern Townships in Québec (Map 17). Both areas very likely represent its northernmost distribution limit in this province.

Conclusion
According to the Catalog of Leaf Beetles of America North of Mexico , there are 17 species of Pachybrachis in the eastern provinces. This study verified 15 of those species (all except P. praeclarus and P. relictus), and discovered two new national and provincial records, both from southernmost Ontario: P. cephalicus and P. luctuosus. Pachybrachis obsoletus is new to NB, and P. peccans is new to PE.
The P. relictus records cited by Fall (1915) (ON: Toronto, Blaisdell Coll.; Scotia Junction, July 27, Wenzel) cannot be confirmed, and there is no evidence P. praeclarus ever existed in eastern Canada.
A review of the distribution and abundance of the seventeen Pachybrachis species reveals four general groups: (1) species distributed from Ontario into at least one province in the Maritimes (P. nigricornis, P. obsoletus and P. peccans); (2) species distributed along the shores of the Great Lakes (Erie, Michigan and Ontario) and rivers (Ottawa, Saguenay and St. Lawrence), but unknown from central and northern ON and QC (P. bivittatus, P. hepaticus hepaticus, P. othonus othonus, P. pectoralis, P. spumarius and P. trinotatus); (3) rare species exclusively from southern ON (P. calcaratus, P. cephalicus, P. luridus, P. subfasciatus and P. tridens) and/or with an additional disjunct population in QC (P. atomarius and P. luctuosus); and (4) species having the northernmost extension of an eastern US distribution into the southeastern Townships of QC (P. m-nigrum). There are no Pachybrachis that could be considered arctic, subarctic, or boreal species; no specimens were found from Labrador or Newfoundland; and all species had southern affinities.
Pachybrachis bivittatus, P. hepaticus and P. peccans are transcontinental species extending from the Atlantic to the Pacific Oceans. They are common across eastern Canada, and have been collected rather recently (1990s -present).
A large group of species found in this study share a similar eastern United States Pachybrachis distribution, occurring from the Atlantic coastal states into the Great Plains: P. atomarius, P. luridus, P. m-nigrum, P. nigricornis, P. obsoletus, P. othonus othonus, P. pectoralis, P. spumarius, P. subfasciatus, P. tridens, and P. trinotatus Barney, unpublished data). Pachybrachis nigricornis, P. obsoletus, P. othonus othonus, and P. pectoralis have all been collected within the last 20 years and probably have viable populations, but P. atomarius, P. calcaratus, P. luridus, P. subfasciatus, P. tridens, and P. trinotatus have not been collected in over 30 years (luridus in over 70 years) and may be considered extirpated from eastern Canada.
The remaining species, P. calcaratus, P. cephalicus, and P. luctuosus, were from the relatively small, southern Carolinian Ecozone, but their North American distribution is not as well defined or widespread as the others Barney, unpublished data). Pachybrachis calcaratus has not been collected in Canada since 1944 and is very likely extirpated from Canadian fauna. Pachybrachis cephalicus may survive in its refugium in the Walsingham Forest (ON). Pachybrachis luctuosus was collected recently in southern Ontario and is probably still surviving there, but we have no recent information on the disjunct population in the Ottawa Valley.
Of course, any faunal survey such as this is only as good as the naturalists and collectors out in the field. There have been five major collectors of eastern Canadian Pachybrachis: J. Ouellet, 680 specimens during 1900s to 1940s;J. F. Brimley, 257 specimens during 1910s to 1950s;W. J. Brown, 234 specimens during 1920s to 1950s;S. D. Hicks, 120 specimens during 1940s and1950;andL. LeSage, 224 specimens during 1980s to 2000s. This demonstrates that 57% of all eastern Canada Pachybrachis ever collected were found by four collectors between 1900 and 1959. The loss of habitat appears to be accompanied by a loss of people monitoring the habitats. Hopefully, the species cited above as possibly being extirpated from eastern Canada are still out there waiting to be rediscovered.
One of the consequences of global warming of the climate is that many plant and animal species will move northward. Woodall et al. (2009) stated that the process of northward migration of trees in the eastern United Stated is currently underway. According to Diffenbaugh et al. (2008) and Woodall et al. (2009), the relaxed cold limitations and a greater accumulation of degree-days should favor several herbivores, but native Pachybrachis species and their host plants could benefit as well of expected warmer conditions.

Map
Map 5. The known distribution of Pachybrachis hepaticus hepaticus in eastern Canada. OL -Ontario Lake; OR -Ottawa River.