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).