Birds of Celebes: Dicruridae. 439 



crest-plumes in different states of perfection". The imperfect and irregular deve- 

 lopment of these fine naked shafts in at least three East Indian species, when 

 adult or even old, seems to suggest that this character is becoming obliterated, 

 in other words, that these hairs are ancestral vestiges derived from a form like 

 Dicruriis hottentottus of Indo-C'hina. 



In the closely-allied genera, Bhringa and Dissemurus, one of the most wonder- 

 ful developments of racket tail-feathers is seen, the outermost pair of rectrices 

 being greatly prolonged, bare-shafted for some distance from the point where 

 they overreach the other tail-feathers, each ending with a long and broad paddle- 

 like racket. In Bhringa the shaft passes mesially through the racket, in Dissemurus 

 the inner web of the racket is very much reduced, but the outer web very broad. 

 (See, also, remarks on Prioniturus platurus and Merops ornatus in the Introduction.) 



The white tips on the axillaries and under wing-coverts, which are best 

 developed in Sangi birds, are sometimes absent in adults from the mainland, 

 while younger Celebes specimens possess them sometimes to as great an extent 

 as those of Siao, or even as adults from Great Sangi. But that they tend to 

 disappear with age in Celebes shows that the birds of the mainland are more 

 advanced in development in this respect. 



The size and extent of the spots on the breast and throat are dependent 

 upon the age of the individual. This has perhaps not always been taken suf- 

 ficiently into consideration by writers on the next species, D. pectoralis Wall. 



-h 169. DICRURUS PECTORALIS Wall. 

 Sula Drongo. 



Dicrurus pectoralis (1) Wall., P. Z. S. 1862, 342; (2) Finscb, Neu Guinea 1865, 170 pt. 

 (Sula); (3) Gray, HL. 1869, I, 285, Nr. 4214; (4) Wald., Tr. Z. S. 1872, VXH, 

 70; (5) Sclat., P. Z. S. 1S77, 101; (6) Salvad., ib. 1S78, 88; (7) Tweedd., t. c. 

 615; (8) id., Ibis 1878, 73; ('6""V M. & Wg., Abb. Mus. Dresd. 1896, Nr. 2, p. 15. 



a. Chibia pectoralis (1) Sharpe, Cat. B. m, 1877, 240; (2) id., P. Z. S. 1879, 247. 



b. Dicruropsis pectoralis (1) Salvad., Ann. Mus. Civ. Gen. 1879, XV, 39; (2) id., Orn. Pap. 



n, IS8], 173 fObi major); (3) Guillem.. P. Z. S. 1885, 571. 



"Sumpolak", Peling and Banggai, Nat. Coll. 



Adult. Like D. leucops Wall, of Celebes, except as regards tbe iris, wbicb is red, not wbite. 



Observation. Otber differences, sucb as smaller size and more brilliant spangles on tbe breast, 

 as mentioned by Sbarpe (a 1), and tbe presence of long recurved bairs sprouting at 

 tbe forehead, on wbicb Salvador! has laid stress, cannot be ad.mitted as discrimi- 

 native characters for this form, since our large series of D. leucops shows that species 

 to be highly variable as regards size, extent and tint of tbe metallic spangles, and 

 the presence and length of the fine hair-like recurved shafts at the forehead, the 

 ditferences being in a large measure due to age and to some extent, we bebeve, to 

 sex and season. Dr. Guillemard (b 3) seems first to have pointed out that tbe 

 recm-ved filaments are absent in many specimens of D. pectoralis (from where ?j, with 

 which he identifies the So'oloo bird, and Mi. Wallace makes no mention of them in 

 his diagnosis of the species, though they are present in the type (a 1). 



