Abstract We describe and illustrate the male, female, and pupa of two new species of Neocorynura from the Colombian Andes, and provide information on their nesting behavior, host plants and social organization. Nests of Neocorynura iguaquensis sp. nov. Smith‐Pardo & Gonzalez and N. muiscae sp. nov. Smith‐Pardo & Gonzalez were found in flat or vertical banks, and contained one to three adult females. The percentage of multi‐female nests varied considerably from 8.3% to 40% of the total of dissected nests at different times in 2000 and 2003. The ovarian development, wing and mandibular wear of females in the nests with two or more females indicated that they were the offspring that remained in the nest before dispersal or a mother and a newly emerged daughter. Pollen taken from the nest cells and scopae of museum specimens showed that both species rely heavily on pollen of asteraceans and may be active year‐round. Details on the nest architecture and comments on the phylogenetic placement of both species are also provided. Direct observations on the multi‐female nests are required to determine whether or not such nests contain temporary assemblages or truly semisocial colonies. Resumen Describimos e ilustramos el macho, hembra y pupa de dos especies nuevas de Neocorynura de los Andes colombianos, y proporcionamos información sobre su biología de nidificación, plantas hospederas y organización social. Los nidos de Neocorynura iguaquensis sp. nov. Smith‐Pardo & Gonzalez y N. muiscae sp. nov. Smith‐Pardo & Gonzalez fueron encontrados en el suelo, en áreas planas o barrancos verticales, y tenían de una a tres hembras adultas. El porcentaje de nidos con más de una hembra varió considerablemente desde 8.3% al 40% del total de nidos disectados a diferentes meses en el año 2000 y 2003. El desarrollo ovárico, desgaste de las alas y mandíbulas de las hembras en los nidos con dos o más hembras indicaron que ellas fueron las crías que permanecieron en el nido antes de dispersarse o una madre con la hija recién nacida. El polen tomado de las celdas de cría y escopas de especimenes de museo mostró que ambas especies dependen principalmente de asteraceas y que podrían estar activas todo el año. También oferecemos detalles de la arquitectura del nidos y comentarios sobre la posición filogenética de ambas especies. Observaciones directas de los nido con más de una hembra son necesarias para determinar si tales nidos son agrupaciones temporales o verdaderas colonias semisociales. Keywords: Neocorynura nesting biologyAndesColombia Acknowledgments This work is dedicated to the memory of Juan Pablo Cárdenas, beloved father of AHS‐P. We thank Daniel Bennett, William Wcislo, M. S. Engel and C. D. Michener, Anne Zillikens and two anonymous reviewers for their comments and suggestions on the manuscript; Paula Montoya and Monica Ospina for their help in the field and their comments on the biology of the species; Carlos Sarmiento and Guiomar Nates‐Parra for lending us some of the specimens for study, and finally The Instituto de Ciencias Naturales, Universidad Nacional de Colombia, for allowing GB to use the Palynological laboratory. We are indebted to Fernando Fernandez, Diana C. Arias and José E. Castillo from the Sección de Entomología of the Instituto de Investigación en Recursos Biológicos Alexander von Humboldt, and El Sistema de Parques Nacionales Naturales de Colombia for their outstanding logistical support and for generously providing both permission to work in the park and lodging to V.G. during this study. Financial support for V.G. and AHS‐P was provided by Idea Wild. This is a contribution of the Division of Entomology, University of Kansas.