ABSTRACT. Social wasp species of Mischocyttarus (Phi) related to M. alfkenii (Ducke) and M. paraguayensis Zikán (Hymenoptera, Vespidae, Polistinae). A revision of the taxonomic status and an identification key are presented for species of the genus Mischocyttarus related to M. alfkenii (Ducke) Silveira (2008) in the first cladistic study of the genus treating all subgenera and species groups. In that work, while limited support was found for monophyly of the subgenus Phi, none of the species groups considered in , or any other grouping of species in Phi resulted monophyletic in a consistent way. An exception was a clade formed by part of the species of the group of M. flavitarsis. However, based on purely phenetic aspects and as reference for further studies, Silveira (2008) presented a revised and extended version of Richards's arrangement of species groups, with new diagnoses.In this study, a revision is presented of the taxonomic status of species-level taxa in two of the species groups of Phi, reported by Silveira (2008) as "M. alfkenii and M. basimacula" and "M. infrastrigatus and M. costalimai" respectively (see below). These two groups comprise a significant portion of the taxonomic diversity of the subgenus in South America, in Andean regions and especially southeastern Brazil from where many species were described by Zikán (1935.
MATERIAL AND METHODSSource collections. This study benefited from loans from various institutions (see below and the Acknowledgments section), and especially from visits to the Fundação Oswaldo Cruz Material examined. A little more than 500 specimens are listed in this article, but considerably more were actually examined during visits to collections, especially to the Zikán Collection in Rio de Janeiro, where large nest series are often available. Types of nearly all specific and subspecific taxa were examined, with exception of M. mamirauae Raw, M. baconi Starr, M. basimacula guatemalensis Richards, and M. basimacula superpictus Richards.Observations and drawings. The specimens were examined under dissecting stereomicroscopes, and drawings were made using a camera lucida adapted to ZEISS SV-11 equipment. Photographs were obtained using a LEICA DFC-420 camera adapted to a LEICA MZ-16 stereomicroscope. Male genitalia were not investigated since previous observations of Phi species (Silveira 2008) did not reveal significant interspecific variation. Terminology was the same utilized by Silveira (2008).