[Mr. Withington, for some years resident in Buenos Ayres, and an ardent collector and observer of its birds, has lately sent me a collection which contained examples of 92 species. His interesting field-notes are given in this paper.] II. _List of some of the principal Localities where Collections have been made, mentioned in this Work._ ANDALGALA (FUERTE DE). A town in the Province of Catamarca, near its eastern boundary. AZUL. A town and district; Pampas of Buenos Ayres: lat. 30°. BAHIA BLANCA. Bay and town on the Atlantic; Province of Buenos Ayres. BARADERO. Town on the Rio de la Plata, north of Buenos Ayres city. CAMPO COLORADO. Near Oran, Province of Salta. CAMPO SANTO. Province of Salta. CAPELLÁN. Province of Catamarca. CARHUÉ. Pampas of Buenos Ayres: lat. 33°. CERRO VAYO. Province of Tucuman. CHUPAT (or CHUBUT). River in Patagonia, in the Territory of the same name. CONCEPCION (or CONCEPCION DEL URUGUAY). A town on the Lower Uruguay, in the Province of Entrerios. CONCHITAS. A small stream in the district of Quilmes, near Buenos Ayres city. This locality was attached by some error to the specimens sent by Hudson to the Smithsonian Institution. COSQUIN. A village in the Sierras, west of Cordova City. CURUMALAN. In the Pampas of Buenos Ayres, 75 miles north of Bahia Blanca. GUALEGUAYCHÚ. A town on the Lower Uruguay, Province of Entrerios. ITAPUA. Territory of Misiones. MERCEDES. A town and district west of Buenos Ayres city. ORAN. A town in the Province of Salta, 50 miles south of the Bolivian border. PARANÁ. A city on the Paraná River, Province of Entrerios. PIGUÉ. In the Pampas of Buenos Ayres, 75 miles north of Bahia Blanca. PUNTA LARA. A point on the Rio de la Plata, near La Plata city. QUILMES. A town and district near Buenos Ayres city. RINCON DE LUNA. A village in the Province of Corrientes. RIO COLORADO. Pampas of Buenos Ayres. RIO QUINTO. Province of Cordova. RIO SAUCE. A stream west of Bahia Blanca. RIO VERMEJO. Province of Salta. SAN ANTONIO (CAPE OF). South of Buenos Ayres city: S. lat. 36° 20′. SAN XAVIER. Territory of Misiones. SENGEL. A tributary of the Chupat River. SENGUELEN. A tributary of the Chupat River. SIERRA DE LA VENTANA. In the Pampas of Buenos Ayres, near Bahia Blanca. TAFI (VALLEY OF). Near the city of Tucuman. TOMBO POINT. On the coast near the mouth of Chupat River. TOTORAL (SIERRES DE). Province of Catamarca. INDEX. _Acahé_, i. 110. Acanthylis collaris, ii. 11. Actiturus bartramius, ii. 189. Actodromas bairdi, ii. 184. ---- fuscicollis, ii. 185. ---- maculata, ii. 183. Æchmophorus major, ii. 202. Ægialitis cantiana, ii. 174. ---- collaris, ii. 173. ---- falklandica, ii. 172. _Afeytado_, ii. 114. _Agachona_, ii. 181. Agelæus flavus, i. 98. ---- ruficapillus, i. 99. ---- thilius, i. 97.