Pachybrachis luridus, Species-Group

Barney, Robert J., 2017, Definition and Revision of theLuridusSpecies-Group of North AmericanPachybrachisChevrolat (Coleoptera: Chrysomelidae: Cryptocephalinae), The Coleopterists Bulletin 71 (1), pp. 1-45 : 3

luridus Species-Group

Group Diagnosis. Small to moderately large species, length 1.90–2.86 mm; dorsum glabrous with coloration ranging from yellow mottled with brown or black markings to black; eyes of males closely to moderately widely separated (IOD 0.10– 0.43 mm); front without ocular lines; protarsal claws of males distinctly enlarged. Median lobe of male genitalia with basal plates simple; distal en-face outline (DEO) highly variable between species, ranging from ALM gently curved with rounded terminus to DEO culminating in a triangular extension of the terminus; in lateral view, shaft varies from ventral surface inflated but truncated to broadly inflated but distinctly narrowed at the basal contraction; beard setae short in patch or in wisps; pencilli absent.

Remarks. I propose the luridus species-group to include ten Nearctic species: P. confusus Bowditch ; P. dilatatus Suffrian ; P. discoideus Bowditch ; P. femoratus (Olivier) ; P. luridus (Fabricius) ; P. rileyi Barney ; P. sherri ae Barney, new species; P. shirleyae Barney , new species; P. subfasciatus (LeConte) ; and P. turbidus (LeConte) . Pachybrachis discoideus and P. rileyi were addressed in Barney (2016a) and will not be redescribed here. While this species-group is not believed to be a natural group, the distinctly enlarged protarsal claws and lack of ocular lines distinguishes the species in this group from other Pachybrachis species in the eastern United States.

Biology. Almost nothing is known of the biology of the members of the luridus species-group . Clark et al. (2004) summarized various plant associations with adults of this species-group, and more are reported here. Many of the species are associated with Quercus spp. ( Fagaceae ). Larvae and larval habitats are unknown; however, the first example of the pupal case of a North American Pachybrachis is presented.