ART. 4 BIRDS OF THE MENTAWI GROUP — RILEY 11 



lus and B. j. icastopterus are larger and lighter colored than B. j. 

 javanicus. The immature of B. j. sipora is much darker than any 

 immature with which I have been able to compare it. I have, how- 

 ever, seen no immatures of B. j. javanicus. 



The wings of the various races mentioned above measure as 

 follows : 



A male from Java, 164 ; female, 166. 



Type of actophilus, North Pagi Id., 192. 



Two females, Sipora Id., 170, 172. 



Two males, Siraalur Id. (icastopterus), 191 (type), 180. 



One unsexed, Niasi Id., 177. 



The United States National Museum does not at present possess a 

 sufficient amount of material from the wide range of the species to 

 permit me to work out the various forms into which it has been pro- 

 posed to divide it. • Some of the races have been separated on very 

 scanty material, indeed, but I prefer to leave the question in abeyance. 



SPILORNIS ELGINI SIPORA Chasen and Kloss 



Spilornis elgini sipora Chasen aud Kloss, Ibis, 1926, p. 278 (Sipora Id., 

 W. Sumatra). 



One male and one female, Sipora. 



While the describers are probably correct in making this a form 

 of /S. elgini and S. miniTnios a form of S. cheela, they are mistaken 

 as regards S. ahhotti and S. klossi, since both are well-marked species. 



/S. ahhotti is similar to S. e. sipora above, but the mantle has the 

 feathers edged narrowly with clay color and the feathers of the crest 

 more broadly tij^ped with black; below, S. ahhotti is quite different, 

 ochraceous tawny (instead of mummy brown), the chest and upper 

 breast being distinctly barred with blackish, with the white spots on 

 the breast and belly smaller. S. ahhotti also is a much larger bird, 

 having a wing in the male ranging from 328 to 360 mm. 



S. klossi Richmond of Great Nicobar Island is the most distinctly 

 marked species in the genus. Quite small and very pale. Swann ^® 

 examined the series in the National Museum and gave a good con- 

 densed description ; a fuller description was given by the describer.*^ 

 To make it a race of S. cheela is only to obscure its great distinctness. 



CUNCUMA LEUCGGASTER (Gmelin) 



Falco leucogaster Gmelin, Syst. Nat., vol. 1, 1788, p. 257 (New South 



Wales). 

 Cuncuma leucogaster Chasen and Kloss, Ibis, 1926, p. 279. 



One immature male, Sipora, October 26. 



" Syn. Accipitres, ed. 2, pt. 3, 1922, p. 137. 

 " Proc. U. S. Nat. Mus., vol. 25, 1902, p. 304. 



