We present the first cladistic analysis of Argia species, focusing on those occurring in North America north of Mexico. Our analysis is based on mitochondrial 16S rDNA and morphological characters of both sexes of adults and immatures. We reexamine classical work on Argia taxonomy and phylogeny. Our results agree considerably with previous hypotheses based morphology in an absence of phylogenetic analysis, and thus our work represents and independent test of these previous hypotheses. Argia is recovered as monophyletic. The clade composed of A. funcki plus A. lugens is basal among the species studied here. The species A. fumipennis, including the three subspecies, appears to be a paraphyletic assemblage, and thus may warrant being considered separate species as originally described. The feasibility of producing a thorough phylogenetic analysis of the entire genus using multiple sources of data is discussed.

The nymphs of eastern North American stonefly genus Cultus are described. Previous misidentifications and putative nymphal descriptions are reviewed. A key separating the late instar nymphs is also provided.

The Neotropical genus Carvalhomiris Maldonado and Ferreira, 1971, is revised. Carvalhomiris brachypterus Maldonado and Ferreira, 1971, its type species, is redescribed and two species are described as new, C. bifurcatus sp. nov. from Ecuador, and C. truncatus sp. nov. from Colombia. Selected external morphological structures of the head, pronotum, metathoracic scent gland efferent area, pretarsus, and egg are documented with scanning electron micrographs for the two new species. Dorsal habitus photographs of macropterous and brachypterous specimens illustrating color variation, line drawings of male and female genitalia of all species, and a key to adults of the species are provided. The potential relationships of Carvalhomiris within Orthotylini are discussed, the genus now being placed in the Zanchius group.

The first key to the Oriental species of the genus is provided. One new species, Lyroda tridentata from Yunnan, China, is described and illustrated. L. salai Giner Marí is first recorded from China.

Many aspects of the biology and organization of Neotropical social wasps in the highlands are unknown. Polybia aequatorialis is a highland wasp of Costa Rica distributed between 1,150 and 3,200 m in altitude, and little information on this species is recorded. We investigated the size of a colony of P. aequatorialis in the Cerro de la Muerte region of Costa Rica, and studied the morphological differences between queens and workers. Measures were taken from 248 reproductive and non-reproductive females, and caste differentiation was analyzed by Discrimination Function Analysis. We did not find a highly pronounced caste distinction in P. aequatorialis, even though ANOVA showed that queens and workers differed in all morphometric measures. The morphological differences between the reproductive and non-reproductive females probably results from a developmental switch, which is a characteristic caste syndrome of Polybia.

Two new species are described, Delia subatrifrons Xue and Du n. sp., and Delia fimbrifascia Xue and Du n. sp. A revised D. alaba subsection of the D. frontella section is studied and a key to this subsection is included.

The genus Mimumesa Malloch from China is reviewed. A key to the species is provided. Two new species, M. melanosomatica, sp. nov. from Yunnan Province, China, and M. nonstriata, sp. nov. from Xinjiang Autonomous Region, China, are described and illustrated, and three species new to China are reported.