18 BULLETIN 117, UNITED STATES NATIONAL MUSEUM. 



bushes, blossomed in April and May. During the dry months the nights were cold, 

 often bitter, the days bright and fresh, accompanied by a strong daily breeze up the 

 A'^alley, lasting from noon until sunset. The mountain slopes which wall in the city 

 of Ollantaytambo have a decidedly arid appearance, the scattered vegetation of cac- 

 tus and stunted bushes being far from adequate to cover the brown rocks and soil. 

 Bordering the stream is a scattered growth of willows, alders, cherry trees, Stenolo- 

 bium, a saxifrage tree (Escallonia), Spanish broom, Baccharis bushes, and others. 

 Well above the valley the slopes and ridges support various grasses. 



Heller Expedition, April 25; July 20-August 14; November 7-12, 

 1915; Chapman Expedition, July 5, 1916; 68 specimens of 27 species. 



Occohamoa Pass (altitude 13,800 feet; camp, 12,500 feet, Puna 

 Zone). — The few specimens collected by Heller in this locality show, 

 as might be expected, that it is in the Puna Zone. The species repre- 

 sented include our only specimens of Thinocorus orbignyanus and 

 Theristicus hranicJcii as well as examples of Cliloejpliaga melanopteray 

 Nettion oxypterum, Colaptes puna, Geossitta tenuirostris , Plirygilus 

 unicolor, etc. 



Heller's description of this station follows: 



We have applied the name Occobamba Pass to the pass leading from the head of 

 the Ollantaytambo Valley to the Occobamba Valley. The Occobamba Pass is trav- 

 ersed by a well-made road over which considerable traffic is carried annually. The 

 pass lies some eight leagues north and above Ollantaytambo and has a summit altitude 

 of 13,800 feet, by aneroid measurement. The rugged, mountainous character of most 

 Andean passes is quite wanting here, and it is a great relief to find such a region as this, 

 with gently sloping, rounded hills and wide shallow valleys. In the neighborhood of 

 the pass the country has the appearance of a rolling prairie on a gigantic scale. 



The hills, when we visited the region in July, were covered by a tliick growth of 

 dried grass as far as the eye could see. No nude rock surfaces, no snow fields, no tree 

 growths were visible; all was a rolling sea of brown grass. The climate is dry compared 

 to the forested montafia country farther north, but the pass receives considerably more 

 rainfall than Ollantaytambo owng to its greater elevation and proximity to the summit 

 ridges. During our stay in July the weather was very cold, the coldest we experienced 

 in Peru. The nights were bitter cold, freezing the margins of running streams as well 

 as vessels of water actually inside the tent. The mornings, though sunny, were cold, 

 until 9 a. m., and the climate was bracing even at midday. Shrubs and conspicuous 

 herbs were quite lacking here. The bushy growth bordering the stream ceases at 

 12,500 feet altitude. Rock surfaces were seen in some of the higher tributary valley 

 above the limits of vegetation, where a variety of formation of slates, shales, basalts, 

 and granites were noted, but in the main valley disintegration had gone very far, all 

 the hills being soil-covered, and supporting a growth of grass. In the neighborhood of 

 villages, at altitudes of 11,000 to 13,000 feet, potato culture is extensively engaged in, 

 the soil being rich black loam. Most of the valleys are, however, devoted to grazing 

 herds of llamas, alpacas, sheep, horses, and mules. 



Holler Expedition, July 20, 21, 1915; 10 specimens of 12 species. 



Occobamba Valley (altitude, 9,100 feet, humid Temperate Zone). — 

 One of Heller's stations above Ollantaytambo. The presence hero 

 of Grallaria riifula obscura, Heliochera cristata, Dlglossa personata 

 melanopis, and Conirostrum cinereum cinereum indicates that it is in 

 the humid Temperate Zone, apparently at its lower margin. Holler's 

 description of this locality follows: 



