Davis 1946 Pipilo fuscus 48. Guadalajara, Jalisco, Mex. to San Luis Potosi, San Luis Potosi, Mex. Aug. 7, 1946 Guadajara to San Luis Potosi. Potosinus undoubtedly cuts across to the eastern Plateau in Hidalgo, Puebla + Veracruz, connecting with the Valley of Mexico population of fuscus, probably around Tacuaca. There may be other cross-connections between fuscus and fotosinus between Tacuaca and San Juan de Lagos. From what we have seen, fotosinus is a bird of arid, desert-like country. The most distinct Mexican race of P. fuscus seems to be rutilus, which is evidently pretty far along the road to speciation. Fuscus seems to connect climally with fotosinus, which again connects with perfallidus (if this is a good subspecies), which connects with mesoleucus intermedius. Butilus seems to be sharply cut off. In Tacuaca, it was stopped by a 750 ft ridge, which would constitute no barrier to such mountain-climbers as fuscus + fotosinus. The status of the birds of the Rio de Temascaltepec Valley is in doubt.