586 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. 39. 



males alone unless otherwise specified. Individual variation in the 

 group is not excessive, although there is usually some difference in 

 the shade and extent of the blue ; so that the characters are preserved 

 with fair uniformity. Newly molted birds are usually of brighter, 

 sometimes slightly more purplish, blue, than when much worn, but 

 this color does not appear otherwise to undergo any material change. 



Like so many other birds of the same general region, some of the 

 forms of HypotJiymis are peculiar in their geographical distribution. 

 The race of HypotJiymis azurea occurring on the Tambelan Islands, 

 off the western coast of Borneo, is H. a. opisihocyanea"' of the Anamba 

 Islands, instead of the Borneo-Malay Peninsula form. The sub- 

 species found on the island of Car Nicobar, Nicobar Islands, Hypo- 

 tJiymis azurea idiocJiroa,^ is much more like HypotJiymis azurea pro- 

 pJiata '^ from the Malay Peninsula than like HypotJiymis azurea calo- 

 cara^ from the other Nicobar Islands. Still more remarkable, and 

 showing again the apparent kinship or parallel development of forms 

 from the western coast islands of Sumatra with forms from the Anda- 

 man Islands that exists in birds of other genera, is the close similarity 

 of HypotJiymis azurea consohrina, from Simalur Island, and Hypo- 

 tJiymis azurea ricJimondi,^ from Engano Island, to HypotJiymis azurea 

 tytleri, from the Andaman Islands, and their great difference from 

 both HypotJiymis azurea propJiata/ of the Sumatra mainland, and all 

 the island races that geographically intervene between Engano and 

 Simalur islands. Furthermore, the bird from the Pagi Islands, Hypo- 

 tJiymis azurea leucopJiila,^ which is the one of these island races geo- 

 graphically nearest HypotJiymis azurea ricJimondi,^ from Engano, is, 

 in appearance, the most different; while between HypotJiymis azurea 

 amelis,^ from Nias, and HypotJiymis azurea consohrina, from Simalur 

 Island, there comes in the totally distinct species HyjJotJiymis ahJ)otti, 

 on Pulo Babi and Pulo Lasia. 



The literature relating to this group of very beautiful little fly- 

 catchers is to be found mostly as scattered notes on individual species 

 in systematic and faunal papers; and the only complete recent 

 account of the genus is that of Dr. R. B. Sharpe, in the Catalogue of 

 Birds in the British Museum, volume 4, 1879, pages 273 to 279. 



The material which has been available as the basis of this review of 

 HypotJiymis consists of 205 specimens, in large part of the fortunately 

 excellent series (180 specimens) in the U. S. National Museum. 

 Aside from this we are indebted for altogether 25 specimens to Mr. 

 J. H. Fleming, and to the Academy of Natural Sciences of Philadel- 

 phia, through the kindness of Mr. Witmer Stone. 



« See p. 602. t? See p. 610. ^ See p. 607. 



b See p. 604. e See p. 613. ^Seep. 613. 



c See p. 597. /Seep. 597. * See p. 608. 



