Order Primates Author Colin P. Groves text 1993 Smithsonian Institution Press Washington and London Editor Don E. Wilson Editor DeeAnn M. Reeder Mammal Species of the World (2 nd Edition) 243 277 book chapter 193461 10.5281/zenodo.7353122 0df816bd-0cef-463a-94c2-b03e13ea7128 1-56098-217-9 7353122 Hylobates leucogenys Ogilby, 1840 . Proc. Zool. Soc. Lond., 1840:20 . TYPE LOCALITY: Laos , Muang Khi ( Fooden, 1987 ) . DISTRIBUTION: SW Yunnan ( China ) to 19°N in Vietnam . STATUS: CITES - Appendix I; U.S. ESA - Endangered. SYNONYMS: henrici. COMMENTS: Subgenus Nomascus . Separated from concolor by Dao (1983) and Ma and Wang (1986) .