TEND LIZARDS OF THE GENUS PROCTOPORUS FROM BOLIVIA AND PERU 1HOMAS UZZELL Department of Biology and Peabody Museum of Natural History, Yale University Abstract Four species [P. pachyunis Tschudi, P. bolivianus Werner, P. guentheri (Boettger), P. ventrimaculatus Boulenger] occur in Boliv-ia and Peru. The first three (the P. pachyiirus group) have an undivided translucent disc in the lower eyelid, a median occipital, two or three supraoculars, and squarish pregulars not forming chevrons. This group resembles P. striatus (Peters) in the last character, but differs from it in the first three. P. pachyurus (17 examined) and P. bolivianus (158) occur at about 2500-3800 m above sea level on the eastern Andean slopes, the former in cen-tral Peru, the latter in southern Peru and northern Bolivia. P. guentheri (30) occurs parapatrically at lower elevations (1000-2516 m). Although the hemipenes of P. bolivianus and P. guen-theri resemble each other rather than that of P. pachyurus, in most respects P. bolivianus and P. pachyurus are more similar to each other. Specimens of P. bolivianus from the upper reaches of the Rio Urubamba differ from those from the lower Rio Urubamba valley in size, ventral coloration, presence of a loreal, and number of anterior supralabials. A small sample from Cuzco resembles those from the lower Rio Urubamba valley in absence of a loreal and in femoral pore number, but resembles specimens from the POSllilA 142: 39 p. 30 JANUARY 1970.