Birds of Celebes; Dicaeidae. 
451 
in the Himalayas is known, that it is impossible to doubt that they are very 
closely related (see figures of both in Ibis 1874, pi. I); the Ceylonese bird has 
changed in wing-structure, but very little in coloration, showing how a generic 
diffe rence may be evolved, while specific characters remain con- 
stant^). Acmonorhynchus quadricolor of the Philippines has the back red, but 
the subterminal or basal part of the feathers black, “producing a mottled appear- 
ance” (Sharpe), and, if Mr. Keeler’s hypothesis — that the tip shows the 
more recent and the basal part the former colour of a feather — be correct (?), 
then A. quadricolor once had a black back, which would make it somewhat like 
A. vincens and Pachyglossa. It would be of interest to know if the immature 
PhilijDpine bird has a black back. The forms of the Celebes area and Flores 
with their olive-green upper surface (without black bases) are much more dis- 
tinct. An investigation of the pigments in them and in Packyglossa might be 
made with advantage. 
From the foregoing it appears that Pachgglossa has some claim to be re- 
garded as the ancestor of Acmonorhynchus. In the East Indies it has undergone 
much change, whether by reason of different food, climate, closer interbreeding, 
different animal foes, or whatever else may be supposed to have caused it to 
develop in fresh directions. This unknown quantity has not been encountered 
by the bird in the Himalayas, or it must have changed there also. Mr. Wallace 
has already (c 2) spoken of A. aureoUmhatus as a Himalayan type in Celebes, and 
though it cannot now be regarded as one “unknown in any Malay island”, since 
Mr. Biittikofer shows that the forms of Sangi, Flores, one of the Philippines, 
and Ceylon are of one genus, there is certainly some reason to think that it 
and the others originally came from the Himalayas. 
Acmonorhynchus, with the closely allied genera Piprisoma, Pachyglossa and 
Prionochilus, does not occur in the Australian Region, being unknown east of 
Timor and the Molucca Strait. The relationship of A. aureoUmhatus with Dicaeum 
may be seen in the finely serrated cutting edges of the terminal third of its 
bill, a character which, as Oates shows, connects the true Dicaeidae (a family 
in which some other genera are wrongly included by Dr. Sharpe) with the 
Nectariniidae. 
* 178. ACMONORHYNCHUS SANGIRENSIS (Salvad.). 
Sangi Yellow-sided Flower-pecker. 
Plate XXVII. 
a. Prionochilus sanghirensis (1) Salvad., Ann. Mas. Civ. Gen. IX, 1876, 59; (2) Meyer, 
Isis, Dresden 1884, 6; (3) Sharpe, Oat. B. X, 1885, 71; (4) W. Bias., Ornis 
1888, 591. 
See, also, our siieculations on the origin of the Pernes and Spkaeti under Pernis celebe/uis, and of 
certain Kingfishers under Ceycopsis. 
57 * 
