Pachybrachys pubescens, : sensu Olivier, 1808

Barney, Robert J., 2019, Definition and Revision of the Pubescens Species-Group of North American Pachybrachis Chevrolat (Coleoptera: Chrysomelidae: Cryptocephalinae), Including Descriptions of Three New Species, The Coleopterists Bulletin 73 (4), pp. 1017-1048 : 1018

pubescens species-group

Group Diagnosis. Medium-size species, males measuring 1.86–3.57 mm in length. Dorsum pubescent with coloration ranging from entirely yellow to entirely black, with many variations in between. Eyes of males contiguous to widely separated (IOD = 0.00– 0.58 mm); front without ocular lines. Protarsal claws of males not significantly enlarged. Median lobe of male genitalia with basal plates simple, no denticles or penicilli; beard setae short in patches.

Remarks. The pubescens species-group, as proposed here, is an artificial grouping of species found primarily in the southwestern USA and Mexico. The distinguishing characteristic of this group is the distinctly pubescent dorsal surface. I propose the pubescens species-group to include 12 species: P. analis LeConte ; P. baja Barney , new species; P. connexus Fall ; P. donneri Crotch ; P. gilberti Barney , new species; P. morosus Haldeman ; P. integratus Fall ; P. madera Barney , new species; P. thoracicus Jacoby ; P. vigilans Fall ; P. wickhami Bowditch ; and P. xanti Crotch. While Pacybrachis pubescens Olivier is no longer a valid name, it was selected as the basis for the species-group name since it was the first species identified and the name conveys the distinguishing characteristic of the group.

Biology. Almost nothing is known of the biology of most species of North American Pachybrachis . In the pubescens species-group, however, a large number of potential host plants are listed on labels. The following seven plant families and respective genera and species names were verified using theplantlist.org: Ambrosia monogyra (Torr. & A. Gray) Strother & B. G. Baldwin , Ambrosia salsola (Torr. & A. Gray) Strother & B. G. Baldwin , Artemisia sp. , Baccharis sp. , Ericameria nauseosa (Pall. ex Pursh) G. L. Nesom & G. I. Baird , Grindelia hirsutula Hook. & Arn. (all Asteraceae ); Quercus buckleyi Nixon & Dorr , Quercus falcata Michx. , Quercus fusiformis Small , Quercus gambelii Nutt. , Quercus incana Bartram , Quercus marilandica (L.) Münchh., Quercus mohriana Buckley ex Rydb. , Quercus × undulata Torr. (Fagaceae) ; Acacia constricta (Benth.) Seigler & Ebinger , Acacia greggii A. Gray , Acacia rigidula Benth. , Cytisus scoparius (L.) Link, Mimosa aculeaticarpa Ortega , Parkinsonia sp. , Prosopis sp. , (all Fabaceae ); Eriogonum fasiculatum Benth. (Polygonaceae) ; Adenostoma fasciculatum Hook. & Arn. (Rosaceae) ; Populus trichocarpa Torr. & A.Gray ex Hook., Salix sp. ( Salicaceae ); Larrea divaricata Cav. , Larrea tridentata (Sessé & Moc. ex DC.) Coville (Zygophyllaceae) .