46 Bulletin American Museum of Natural History [Vol. XL VII 



Through individual variation in the general tone, specimens from either 

 of the series can be selected which are mutually indistinguishable in the 

 color of the upperparts. It is quite different, however, with the ventral 

 surface. In the northern form (H. r. pasha) it is pale yellowish white, 

 varying in different specimens from dull whitish to faintly yellowish on 

 the median area from the throat to the anal region, with usually a large 

 whiter pectoral area, the sides being darkened by the dark basal portion 

 of the hairs showing through the superficial light tipping. The chin and 

 throat are a little browner than the foreneck and breast, being sometimes 

 dull yellowish brown, but rarely approaching rufous. The median 

 portion of the extreme base of the under side of the tail has sometimes 

 a slight rufous tone. The outer edge of the forearm and the upper surface 

 of the manus vary from dark rufous to brownish rufous, but the inside of 

 the forearm is pale like the ventral surface, usually without trace of 

 rufous. 



In specimens of the other extreme, taken south of the Ituri near 

 Avakubi, the whole lower surface of the body has a strong rufous tone, 

 the throat, foreneck, sides of breast, inguinal region, and entire inner 

 surface of both fore and hind limbs are intense vivid rufous, as is also a 

 conspicuous median patch at the base of the under side of the tail, and 

 the upper surface of the fore and hind feet are also red. The median 

 ventral area, from the chest to the lower abdomen, is pale rufous grizzled 

 slightly with black. 



The three forms may be characterized as follows. 



1. Light northern form: Underparts superficially pale, the hair-tips whitish or pale 



yellowish, usually a rather distinct narrow median light band (often broad- 

 ening at pectoral region) contrasting with a much darker and broader area on 

 either side from axillae to loins; throat and inside of limbs light, uniform in 

 color with the central light portion of ventral surface, except wrists; out- 

 side of hind limbs like back ; outer edge of forearm and upper surface of feet 

 pale rufous. On hind limbs the brownish-rufous tone is usually restricted to 

 upper surface of feet; in exceptionally erythric specimens it may extend to 

 the lower leg and include the inner surface as well as the outer, thus forming a 

 dull rufous band just above the ankle, and even extend up the inner side of 

 the leg, with a similar extension of rufous on the inner surface of the lower 

 forearm H. r. pasha (Schwann) . 



2. Darker middle form: Underparts darker, nearly uniform except for a small 



sharply defined white pectoral area, the hairs ringed basally with black and 

 buff- tipped; throat and inside of limbs pale or dull rufous, in contrast with 

 abdominal region; outer surface of hind limbs like back; outer edge of fore 

 limbs intense rufous, which encircles the lower forearms and lower legs and 

 includes the upper surface of fore and hind feet. 



H. r. medjianus, new subspecies. 



