PROC. BIOL. SOC. WASH. 96(1), 1983, pp. 103-109 GEOGRAPHIC VARIATION IN CHLOROSPINGUS OPHTHALMICUS IN COLOMBIA AND VENEZUELA (AVES: THRAUPIDAE) Storrs L. Olson Abstract. — Geographic variation in the montane species Chlorospingus ophthalmicus was studied in specimens from the Andes of Colombia and Vene-zuela. There are two distinct subspecies groups in this area that were formerly treated as separate species. The white postocular spot is lacking in the flavopectus group, which has five representatives in Colombia, including two described as new (C. o. trudis n. subsp. and C. o. exitelus n. subsp.). Additional taxa are found in Ecuador and Peru. In the ophthalmicus group there are five named subspecies in Colombia and Venezuela, as well as two populations of intergrades or undetermined status. In this group, the subspecies C. o. jacqueti has three curiously disjunct populations separated by distinct intervening forms. Specimens of the flavopectus group are reported from a locaUty only 40 km from the nearest known population of the ophthalmicus group, which suggests the possibility of determining whether two distinct species are actually involved. Further field work and collecting are needed to resolve some of the intriguing problems in the evo-lutionary history of C. ophthalmicus in Colombia and Venezuela. The Common Bush-Tanager, Chlorospingus ophthalmicus, exhibits complex variation through its extensive range from Mexico through Argentina. A large series of specimens from Colombia in the National Museum of Natural History, Smithsonian Institution (USNM), most of which had not previously been iden-tified to subspecies, prompted the following revision. To effect this, I assembled material from other institutions, including representation from Venezuelan pop-ulations. Although I have included my observations on the Venezuelan speci-mens, these are tentative and more material will have to be consulted before the systematics and distribution of some of the forms of C. ophthalmicus are properly understood in that country. The spelling of Colombian place names, and their location by department, conforms with that of Paynter and Tray lor (1981) and is not necessarily that found on specimen labels or in my previous pubhcations. The distribution of the various populations of C. ophthalmicus in Colombia and Venezuela is shown in Fig. 1. Chlorospingus ophthalmicus jacqueti Hellmayr, 1921 Type-locality. — Gahpan, Cerro del Avila, near Caracas, Venezuela. Characters. — White postocular spot and dark throat speckles present. Throat only slightly tinged with buffy. Crown color relatively light, rather grayish brown. Yellow breast-band only moderately suffused with orangish. Range. — Inexplicably disjunct. Found in northern Venezuela from Miranda west to Carabobo, then in Trujillo (and extreme eastern Merida according to
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