1907.] 



MONKEYS FROM THE AMAZONIAN REGION. 



93 



about ^ to 1 of the width between the eai'S and widening slightly 

 backwards, but in no specimen acquiring the double ploughshare- 

 shape of the rust-coloured patch of the Midas rufiventer type. In 

 young individuals this patch is rather more greyish, while in 

 more aged specimens it becomes nearly white. In length it 

 extends as far as the posterioi- border of the occipital region. 



A7-tns. Outer side from shoulder to elbow of the same sooty 

 blackish-brown as the whole shoulder region ; fore-arms and 

 hands decidedly black. 



Legs. Outer side of the same intensely mottled colour as the 

 entire hip-region as far as to the foot ; the foot itself of the same 

 black as the hand. 



Text-fie-. 22. 



Back view of head of Midas (jriseovertex. 



Yentral aspect. — General colour light reddish rusty, decidedly 

 lighter than in Midas rufiventer. It embraces the whole area 

 from the middle of the throat, breast, and belly, inner side of arms 

 and legs, and a short distance beyond the insertion of the tail on 

 its under side (some 5 cm.). On the flanks the dorsal and ventral 

 colours are very abruptly separated, it being noteworthy that the 

 I'usty-coloured hairs of the abdominal side ai-e only about half as 

 long as the adjacent dark-coloured haii's of the dorsal part. 



Tail long, exceeding the length of the body by that of the head. 

 Colour the same black as of the fore-arms and hands, but here 

 and there with rows of hairs with light brownish tips, which may 

 be interpreted probably as the vestiges of an annular ai-rangement. 



Midas imperator, sp. n. 



In general aspect, especially in coloiu', somewhat similar to 

 M. lahiat'us GeofFr., M. illigeri, and M. loeddelUi, but easily dis- 

 tinguished by the immense white moustache, which becomes 



