THE DOUROUCOULIS. 171 



Distribution. This species is rather rare, but it has been 

 obtained at Ega and at Tabatinga on the Upper Amazons ; 

 on the Ucayali, and near Yurimaguas on the Huallaga River 

 in the warm and humid virgin forests in fact, generally along 

 the Peruvian Amazons. 



In speaking of his collections made at Ega on the Upper 

 Amazons, which he describes as a fine field for a Natural 

 History collector, Mr. Bates gives an interesting account of 

 the Night-Apes, called " Ei-a " by the Indians, observed by 

 him during his various journeys. " Of these I found two 

 species (Nyctipithecus trivirgatus and N.felintis) closely re- 

 lated to each other, but nevertheless quite distinct, as both 

 inhabit the same forests, namely, those of the higher and drier 

 lands, without mingling with each other or inter-crossing. They 

 sleep all day long in hollow trees, and come forth to prey on 

 insects and eat fruits only in the night. One cannot help 

 being struck by this curious modification of the American 

 type of Monkeys, for the Owl-faced Night-Apes have evidently 

 sprung from the same stock as the rest of the Cebidce, as they 

 do not differ much in all essential points from the Whaiapu- 

 Sais (Callithrix) and the Sai-miris (Chrysothrix). They have 

 nails of the ordinary form on all their fingers, and semi- 

 opposable thumbs ; but the molar teeth (contrary to what is 

 usual in the Cebidce) are studded with sharp points, showing 

 that their nocturnal food is principally insects. 



f< I kept a pet animal of N. trivirgatus for many months, a 

 young one having been given to me by an Indian compadre 

 as a present from my newly-baptized godson. These Monkeys, 

 although sleeping by day, are aroused by the least noise, so 

 that, when a person passes by a tree in which a number of 

 them are concealed, he is startled by the sudden apparition of 



