398 BULLETIN 15 3, UNITED STATES NATIONAL MUSEUM 



others indicate that the extent of individual variation is great. Van 

 Someren,'* on the otlier hand, feels that jacksoni may contain three 

 races, as follows: 



1. Uganda birds having the heads purer white, the back of the 

 head and the mantle on the average bluer than in Kikuyu birds; 

 wings (male) 125-131, (female) 123-127; bill from nostril (male) 

 26-38 millimeters. 



2. Kikuyu to Molo and Escarpment (typical jacksoni) ; general 

 color of hind head and mantle more golden green; wings 130-145 

 millimeters (not 140-144 as Granvik ^^ misquotes) : bills from nostril 

 to tip (male) 35-41 millimeters. 



3. Birds from Sherengani Hills, north end of Elgeyu Escarpment ; 

 males with a distinct bluish wash on the head and mantle; wings 

 120-133 millimeters; bill from nostril (male) 27-37 millimeters. 



I find that the greenish or bluish sheen of the feathers is very 

 variable in birds from one locality, and consequently that that 

 character can not be used in the way Van Someren intimates. Gran- 

 vik writes that the bluish color is characteristic of youngish birds 

 and that older ones are greener. I find just the opposite to be true. 

 The chances are that both young and old vary in this respect and 

 that the difference of opinion is due to the particular specimens that 

 happened to comprise the two series. 



If we take the measurements of a series of seven adult males and 

 five adult females (all from the region given by Van Someren for 

 " typical jacksoni ") we find the following : 



Males: Wing 134-142.5 (average 138.5); tail 162-213 (average 

 198.4) ; culmen from base 40-52 (average 47.8 mm.) 



Females: Wing 126-138 (average 130); tail 131-206 (average 

 185), culmen from base 34-47 (average 39.2 millimeters). 



To make the bill measurements more comparable with those given 

 by Van Someren, it may be mentioned that the total length of the 

 culmen exceeds the distance from the anterior end of the nostril to 

 the tip of the bill by from 8-12 millimeters. 



This species may be distinguished from all the others of its genus 

 by the fact that it has no white spots on the remiges or rectrices in 

 any plumage stage. The white throat and head is also a good char- 

 acter, but this is somewhat variable, and in P. pwyureus white 

 feathers occur not uncommonly on the head region. An immature 

 male jacksoni from Ngong, near Nairobi, in the Museum of Com- 

 parative Zoology (A. Loveridge coll.) has no white at all, the whole 

 liead and throat being glossy metallic green like the mantle and 

 breast. Granvik " records a specimen wliich entirely lacks the 



"Jouin. f. Ornith., 1923, Souderheft, pp. 111-114. 

 " Nov. Zool., vol. 29, 1922, pp. 82-83. 

 '^Journ. f. Ornith., 19L'3, Souderheft, p. 113. 



