Accepted by J. Gibbs: 31 Oct. 2017; published: 13 Dec. 2017 ZOOTAXA ISSN 1175-5326 (print edition) ISSN 1175-5334 (online edition) Copyright © 2017 Magnolia Press Zootaxa 4363 (4): 535–543 http://www.mapress.com/j/zt/ Article 535 https://doi.org/10.11646/zootaxa.4363.4.5 http://zoobank.org/urn:lsid:zoobank.org:pub:A82FCBB1-FE4C-49C8-B1FB-C35B5AEE3234 Coelioxoides piscicauda sp. nov., a new cuckoo bee from southeastern Brazil with a key to the species of Coelioxoides Cresson (Hymenoptera: Apidae) LÉO CORREIA DA ROCHA-FILHO 1 , JOSÉ CARLOS SERRANO & CARLOS ALBERTO GARÓFALO Departamento de Biologia, Fac. de Filosofia, Ciências e Letras de Ribeirão Preto -FFCLRP, Universidade de São Paulo-USP, 14040- 901, Ribeirão Preto, São Paulo, Brazil. 1 Corresponding author. E-mail: correiadarocha@yahoo.com.br. Tel 00 55 16 3603 3704. ORCID 0000-0002-3431-6009. Abstract A new species of Coelioxoides Cresson (Apidae), Coelioxoides piscicauda sp. nov. Rocha-Filho from São Paulo State, Brazil, is described. A key to the four recognized species of the genus, C. exulans (Holmberg), C. piscicauda sp. nov., C. punctipennis Cresson, and C. waltheriae Ducke, is provided. In addition, new host records of Coelioxoides are presented as well as a compilation of published data on species of Tetrapedia Klug associated with this cleptoparasitic genus. Key words: Apinae, cleptoparasite, host association, new species, taxonomy Resumo Uma nova espécie de Coelioxoides Cresson (Apidae), Coelioxoides piscicauda sp. nov. Rocha-Filho do estado de São Paulo, Brasil, é descrita. É fornecida uma chave de identificação para as quatro espécies reconhecidas no gênero: C. exu- lans (Holmberg), C. piscicauda sp. nov., C. punctipennis Cresson e C. waltheriae Ducke. Além disso, são apresentados novos registros de hospedeiros para as espécies de Coelioxoides além de uma compilação de dados já publicados sobre as espécies de Tetrapedia Klug associadas com este gênero cleptoparasita. Resumen Una nueva especie de Coelioxoides Cresson (Apidae), Coelioxoides piscicauda sp. nov. Rocha-Filho del estado de São Paulo, Brasil, es descrita. Se proporciona una clave de identificación para las cuatro especies reconocidas en el género: C. exulans (Holmberg), C. piscicauda sp. nov., C. punctipennis Cresson y C. waltheriae Ducke. Aun más, son presentados nuevos registros de hospederos para las especies de Coelioxoides además de una compilación de datos ya publicados sobre las especies de Tetrapedia Klug asociadas con este género cleptoparásita. Introduction Coelioxoides Cresson (Apidae) consists of slender, dull, black, and small to medium-sized bees restricted to the New World (Michener 2007). A taxonomic review was carried out by Roig-Alsina (1990), who recognized three species that range from northern Mexico to central Argentina. Given that the biological data of Coelioxoides known until that revision were limited to a few floral and distribution records (Ducke 1908; Bertoni 1911), the cleptoparasitic behavior of those species was assumed on the basis of morphological features of females such as the absence of scopa and specialized apical sterna (Roig-Alsina 1990). In a study on the nesting biology of Tetrapedia diversipes Klug in abandoned beetle holes in dead tree trunks and trap-nests, Alves-dos-Santos et al. (2002) described the cleptoparasitic behavior of Coelioxoides waltheriae Ducke, 1908 for the first time, providing the first host record for that genus. The association between those two species was further confirmed by other authors in