4 PROCEEDINGS OF THE NATIONAL MUSEUM vol. 75 



The specimens from Siberut and Sipora are intermediate between 

 the Nias form and that from the Pagi Islands, but on the whole nearer 

 to that of Nias. 



Considering only those forms of the species described from the 

 Sumatran Avest coast islands, we have : 



Demlrophassa vemans mesochloa^ from Nias. 



Dendrophassa vemans folioftila^ from North Pagi. 



Dendrophassa vertmns iniza^ from Simalur. 



The males of D. v. miza are more greenish on the back and are 

 larger than the Nias bird. The wings of the males measure: 166, 

 163, 160.5 mm., and of the female (type), 156 mm. The culmen 

 (from cere) is also longer; in males, 12, 12.5, 11.5; in the female 

 11 mm. 



The male of the Nias form is not so deep a green on the back and is 

 smaller than the Simalur bird. Males measure, wing, 148.5, 157, 154, 

 151, 151.5, 151, 154.5, 154 mm.; culmen (from cere), 10-11.5 mm. 

 Females, wing, 152 (type), 148, 148; culmen (from cere), 10-10.5 mm. 



One male from Siberut measures, wing, 161 ; one female. 147.5 mm. 



Two males from Sipora have the wings 153 and 156 mm. 



A male from Tana Bala, Batu Islands, is here assigned to the Nias 

 form, with wing 149 ; culmen from cere, 11 mm. 



Males from the Pagi Islands are slightly lighter below than those 

 from Nias, and this slight difference also holds in the females. 

 There appears to be little or no difference in size, however. The 

 wings of males measure: North Pagi Island, 148, 151.5, 161, 162.5 

 mm. ; culmen, from cere, 11-11.5 mm. Females from the same island 

 have the wing 154.5, 155, 157.5, 155, 150 (type of polioptila) ; 

 culmen, from cere, 10-11 mm. Males from South Pagi Island have 

 the wing 146, 149 ; culmen from cere, 10-11 mm. 



A male from Engano is like the Nias bird ; it measures, wing, 157 ; 

 culmen, from cere, 11.5 mm. 



The color differences between Pagi and Nias birds are only aver- 

 age and not constant ; some of the Pagi males can not be distinguished 

 from those of Nias. The differences between the females seem to be 

 more constant, but there are only three females in the Nias series, 

 and they were taken later in the season. 



The single female from Siberut is greener below, with the yellow 

 on the belly more restricted than in any specimen before me. and 

 the under tail coverts are very light, with a mere indication of chest- 

 nut along the basal part of the shaft. The latter charaxjter is very 

 variable and there are others in the series just as light or more so. 



It seems to me that no great violence would be done if polioptila 

 were united to mesochloa, in which case only two forms would 



" Obeiholser, Smiths. Misc. Coll., vol. 60, no. 7, 1912, p. 3. 



