32 ILLINOIS ACADEMY OF SCIENCE 



est contrast with the barren west slope and ranges back 

 of it. 



Comparatively few of the mountain slopes have been 

 cleared and placed under cultivation (chiefly to coca.) 

 At San Juan, one of the estates of Dr. Augusto Durand, 

 the writer was hospitably sheltered for ten days while 

 engaged in collecting the parasites of tropical birds. 



After certain delays due to transportation and to fever, 

 work was begun in southern Peru in mid-November. The 

 ensuing four months were devoted to the Titicaca-Poopo 

 basin of Peru and Bolivia, and to northern Chile. 



A few small fishes, Orestias, were obtained at Crucero 

 Alto, on the Pacific-Titicaca divide above Arequipa, at 

 an elevation of 14,650 feet. A narrow pampa forms an 

 easy gradation here between the two slopes. The fish 

 were collected from a network of sluggish ditches beside 

 the railroad, and partially filled with ice and melting 

 snow. In the Titicaca basin collecting was done at 

 Lagunillas and Saracocha, lakes at about 13,500 feet^ 

 and in the Rio de Lampa at Maravillas and Juliaca. 

 Similarly collecting was carried up the Rio de Pucara 

 to Tirapata and La Raya, the latter on the Titicaca- Vil- 

 canota divide at 14,150 feet. No fish occur in the swift 

 water of the upper R. de Pucara, nor in the little sacred 

 lake at La Raya. But siiches (Pygidium rivulatum) were 

 taken just over the divide, both in Lago Verde at equal 

 altitude with La Raya, one kilometer north of the latter, 

 and at Aguas Calientes in the upper river Vilcanota. The 

 latter is a stream of the Urubamba-Ucayli-Amazon sys- 

 tem. 



For want of riding animals four trips were taken on 

 foot, aggregating 200 miles, in order to reach some of 

 the rivers and lakes of the Titicaca-Poopo basin. The 

 first trip was from Puno to Yunguyo, paralleling the west 

 shore of Titicaca. Collections were obtained at Puno, 

 Chucuito, and Yunguyo from the lake itself, from the 

 rivers of Have and Juli, and from the wet meadows 

 of the pampa at Acora, Have, etc. 



The second trip extended from the port of Moho, at the 

 northeast corner of the lake, northwestward to Tirapata. 



