440 MR. E. C. STUART BAKER ON 
¢ Samkok, C. Siam, 21.6.15 
¢ 2 Pak Jong, E. Siam, 18.8.15. 
$ 2 Krabin, C. Siam, 1.11.15. 
All five of these specimens must be placed under this sub- 
species. The stripes on the head and throat are well-developed, there 
is very little rufous wash on either breast or throat. The white 
spots on the tail are smaller than in the Sumatran bird, R. tristis 
tristis, and run across the tail at an angle instead of nearly straight. 
There are five distinguishable races of this Cuckoo. (1) R. ¢. 
tristis from Sumatra, (2) R. ¢t. longicaudatus from Burma, Siam and 
Malay Peninsula, (3) 2. t. montanuws from Northern India, Assam 
to Yunnan, (4) &. t. hainanws from Hainan, and (5) R. t. borneeisis 
from Borneo. 
210. PHd:NICOPHAS ERYTHROGNATHUS. 
Phenicophes erythrognathus, Hartl. Verz. Mus. Brem, p. 95 (1844). 
2 Tung Song, P. Siam, 15.9.15. 
¢ Klong Wang Hip, P. Siam, 6.10.15. 
The wing measurements of these two birds are 171 and 176 
mm. respectively. This Cuckoo belongs to that extraordinary group 
of birds of which it is extremely ditticult to say whether they form six 
genera, six species or merely six geographical races. In colouration 
they are all practically alike, but might be split up into two or three 
races on account of variation in depth of colour, etc. On the other 
hand, they are all structurally different in having nostrils of varying 
shape and placed quite differently in position on the bill. To me it 
appears to be one of those rare cases in which structural differences 
must be held to be of less importance than colour and pattern, and I 
retain all under the one generic head, and consider them to be species * 
only. They cannot be reduced to sub-species, as there are not con- 
necting links to join the one with another. 
211. RHINORTHA CHLOROPHAA CHLOROPH AA, 
Cuculus chloropheus, Raff. Trans. Linn. Soc. xiii, p. 288 (1822). 
Sumatra, 
3 Tung Song, P. Siam, 24.9.15. 
% Maprit, P. Siam, 4.1.16. 
JOURN. NAT. HIST, SOC, SIAM. 
