Messer, Steven J.Cover, StefanLaPolla, John S.2016-03-012016Messer, Steven J., Stefan P. Cover, and John S. LaPolla. 2016. “Nylanderia deceptrix sp. n., a new species of obligately socially parasitic formicine ant (Hymenoptera, Formicidae).” ZooKeys (552): 49-65. doi:10.3897/zookeys.552.6475. http://dx.doi.org/10.3897/zookeys.552.6475.1313-2989http://nrs.harvard.edu/urn-3:HUL.InstRepos:25658516Abstract Obligately socially parasitic ants are social parasites that typically lack the sterile worker caste, and depend on the host species for survival and brood care. The genus Nylanderia has over 130 described species and subspecies, none of which, until this study, were known social parasites. Here we describe the first social parasite known in the genus, Nylanderia deceptrix. Aspects of the biology of the host species, Nylanderia parvula (Mayr 1870), and Nylanderia deceptrix are examined. The data from both the host and the parasite species are combined to better understand the host-parasite relationship.en-USAntsNearcticNew SpeciesSocial ParasitismJournal Article2016-03-0110.3897/zookeys.552.6475