Patterns of episodic emergences of Discoderus LeConte, 1853 (Coleoptera: Carabidae: Harpalinae: Harpalini) in the southwestern United States are presented and discussed. Standardized ground beetle sampling through the National Ecological Observatory Network (NEON) in southern Arizona elucidates mass emergence events of members of Discoderus who exhibit large fluctuations in annual abundance. Although there are no previous quantitative reports of similar events, Discoderus abundance is shown to drive overall carabid abundance in at least one Arizona grassland habitat. Evidence from circumstantial collecting suggests Discoderus obsidianus Casey, 1914 emerged in large numbers in Arizona during the summer of 2022. Remarkably, despite the large number of individuals collected during this event, this beetle is relatively uncommon in insect collections. Taxonomic difficulties in this genus are discussed and images of type specimens are presented.

The diversity of the family Cleridae in the tropical rainforest of the Sierra El Madrigal, Tabasco, Mexico is presented. The systematic collection carried out during an annual cycle revealed 33 species, 14 genera, and four subfamilies. The dominant genus was Phyllobaenus Dejean with six species followed by Plocamocera Spinola with five species. Fifteen species are new records for Tabasco. Phyllobaenus subvittatus (Gorham) represents a new country record for Mexico. The family showed a marked seasonality with greater richness, abundance, and diversity found during the rainy season. Malaise traps were the most efficient collection method, producing 69.7% of the recorded species richness. The nonparametric estimators of Chao 1 (46 species) and Jackknife 1 (51 species) indicate a higher number of species than the observed species value (33 species), which suggests that there are species still to be recorded and more collecting effort to be made. The highest richness and abundance of Cleridae were recorded during the months of June, July, and August, coinciding with the highest recorded rainfall. The Pearson correlation coefficient showed that richness and precipitation have a statistically significant positive relationship (p < 0.05). The data show that the diversity of Cleridae of the Sierra El Madrigal is high and little known (new records), demonstrating the need to continue documenting it.

To provide insight into the mechanisms that enable sympatric-parapatric occurrence of multiple species of leaf beetles belonging to the genus Cassida Linnaeus (Coleoptera: Chrysomelidae: Cassidinae) in northern Japan, host specificity was estimated and mating behavior was observed in the laboratory among six species (Cassida japana Baly, Cassida nebulosa Linnaeus, Cassida rubiginosa Müller, Cassida vibex Linnaeus, Cassida fuscorufa Motschulsky, and Cassida viridis Linnaeus). Although behavioral isolation across the six species was notably incomplete, our data suggest that high host specificity will act as a strong habitat isolation barrier, thus preventing interspecific sexual interaction in the wild. The evolutionary processes that have led to sympatric-parapatric coexistence among Cassida beetles are also discussed.

A new apterous species of Xanthopygina, Ikaros monosiros Chatzimanolis and Solomon, new species, from Colombia is described and illustrated. A revised key is provided for all species of Ikaros Chatzimanolis and Brunke.

Two new genera of Dasytinae (Melyridae) are described from North America: Altovectura Mayor and Gimmel, new genus (type species: Listrus cupreonitens Gorham, 1882) with one new species, Altovectura mojavensis Mayor and Gimmel, new species; and Gracilivectura Mayor and Gimmel, new genus, with two species, Gracilivectura pygidialis Mayor and Gimmel, new species (type species) and Gracilivectura mojavensis Mayor and Gimmel, new species. Three species are transferred from Listrus Motschulsky, 1860 to Altovectura: Altovectura cupreonitens (Gorham, 1882), new combination, Altovectura subcuprea (Champion, 1914), new combination, and Altovectura subcyanea (Gorham, 1882), new combination. Based on characters of the tibiae, pronotum, and male genitalia, both genera are members of a group of genera including Vectura Casey, 1895, Dasytastes Casey, 1895, and Listrocerus Majer, 1999, but are not placed to tribe pending a broader study of relationships within the subfamily.

New records are presented for Melandryidae Leach, 1815 and Tetratomidae Billberg, 1820 from Arizona in the southwestern United States. Six species of the tetratomid subfamily Eustrophinae Gistel, 1856 were previously confirmed from the state and a single melandryid, Rushia californica (Fall, 1907), was questionably listed from the state. We here confirm the latter record and enumerate seven new state records, bringing the total to 14 species in nine genera. Most notably, we report Microtonus elongatus Champion, 1889 as a new country record for the United States, having been previously known only from the type series from Guatemala and Mexico. An annotated checklist of species is presented including new specimen records examined by us, any available digitized occurrence records, and high-resolution images for all species.

There are over 70 species of Pachybrachis Chevrolat known from Arizona. A group of species with tibial spurs on the forelegs of the males consists of three Nearctic species: Pachybrachis coronado Barney, new species, Pachybrachis texanus Bowditch, and Pachybrachis uncinatus Fall. A key to the Tibial Spur Species is given, and a description and figures are provided for each species. New state records are reported for P. texanus and P. uncinatus.

Lanyualtica hsui Lee and Konstantinov, new genus and species, is described from Lanyu Island, Taiwan. It belongs to the Tegyrius genus group and is most similar to Parategyrius Kimoto and Gressitt.

Two new species of the genus Trachys Fabricius from China are described and illustrated: Trachys semicircucollis Peng, new species and Trachys langyashancola Peng, new species.

A new brachypterous species of Dichotomius (Selenocopris) Burmeister, 1846 from Bolivia, Dichotomius abayoyensis Amaya, Condori, Copa-Beltrán, Arias-Buriticá, and Vaz-de-Mello, new species is described with diagnosis, photographs, and discussion of its taxonomic position in the genus. This new species is the eleventh known with the brachypterous condition in Dichotomius Hope, 1938. This species belongs to the Dichotomius geminatus (Arrow, 1913) species group and is related to Dichotomius vidaurrei Nunes and Vaz-de-Mello, 2013. Dichotomius abayoyensis differs from D. vidaurrei in having a longer cephalic process, pronotum with anterior excavation, pygidium with distinct punctures on the entire surface, parameres with a pronounced constriction on their distal lateral margins, subgenital plate present with sclerites without projection, and hind wing reduced with a row of dense setae on the superior margin. This species is known only from the “Chaparral de Abayoy” vegetation, located in Roboré (Chiquitos Province, Bolivia).

Incagonum jcbradleyi Liebherr and Will, new species is described from La Oroya, Junín Department, Peru. The type series was collected during J. C. Bradley's visit to Peru, May–August 1920. The species is taxonomically placed among Peruvian members of the genus and proposed as adelphotaxon to Incagonum hiekei Allegro, Giachino, and Moret. Whereas I. hiekei is characterized by brachypterous flight wings, the metathoracic wings of I. jcbradleyi are vestigial, i.e., not extended beyond the hind margin of the metanotum. Incagonum jcbradleyi exhibits diagnostic features of the genus, including the absence of subapical lateral setae on metatarsomere 4 and the presence of a digitiform basal process on the spermatheca. The latter structure is also part of the spermathecal assemblages of various Glyptolenus Bates species, supporting sister-group status of Incagonum Liebherr and Glyptolenus, both Neotropical genera. Discovery of I. jcbradleyi in Junín narrows the distributional gap between the northern set of Peruvian Incagonum species and Incagonum mateui (Moret) and Incagonum inca (Moret)—restricted to Cuzco and Puno departments—at the same time suggesting that substantial biodiversity of Peruvian Incagonum remains to be discovered in the intervening departments of Huancavelica, Ayacucho, and Apurímac.

The third instar and pupa of Gymnetis merops Ratcliffe, 2018 (Coleoptera: Scarabaeidae: Cetoniinae: Gymnetini) are described and illustrated for the first time based on specimens collected from Lambayeque, Lima, and Ica in western Peru. Notes on the distribution and natural history of the species are included, and the third instar of G. merops is placed in the most recent key to the third instars of Gymnetis, which now includes eight species.