eae PROCEEDINGS OF THE NATIONAL MUSEUM. 293 
adult, that is, the under side is rather heavily streaked with dusky but 
with the new feathers of the adult plumage protruding on the rump, 
consequently in a plumage corresponding to my No. 92721, from Bering 
Island, May 5, which had the ovaries in such a condition that she was 
probably going to breed that spring. 
Henson’s bird agrees in the minutest details with my Bering Island 
and Kamehatkan birds (Res. Orn, Expl. Kamtsch., ete., pp. 203, 204; 
Proc. U. S. Nat. Mus., x, 1887, pp. 139-141). 
-The specimen measures as follows: (U. 5. Nat. Mus. No. 120720), 
2 adol.; Hakodate, March 15, 1884; H. V. Henson coll. No. 9): Wing, 
400"; tail feathers, 237"; chord of culmen from cere, 26™™"; tarsus, 
65"™. middle toe, without claw, 55™™", 
Cuculus kelungensis SWINi. (165) 
The three specimens of Cuckoos in the collection represent three dif- 
ferent stages of this species. The series is very interesting, Inasmuch 
as it shows that the broadly-barred species is quite as polymorphic as 
the common European Cuckoo. We have in fact here to deal with a 
eurious kind of dichromatism, the character of which is still wrapped 
in mystery. 
U.S. Nat. Mus. No. 120566, Henson No, 146, Hakodate, August 30, 
1884, is a female in the rufous stage or phase, apparently adult. 1 say 
“stage or phase,” because it is not yet certain whether this peculiar 
plumage represents a transient stage only or a permanent phase. The 
facts indicate, indeed, that it is a permanent phase in some individuals, 
and an intermediate stage in others, for Naumann (Naturg. Vog. 
Deutsehl., v, Pl. 128, fig. 1) figures a female, in transition from the 
rufous plumage to the typical adult gray garb, while in the text (p. 203) 
he asserts that he once shot a female cuckoo in the genuine rufous 
plumage, which was molting into a still brighter rufous one. The ob- 
servation by Naumann (loc. cit., p. 203) on the European Cuckoo, that 
the central pairs of the tail-feathers are of more uniform length and 
Jess graduated in the rufous birds, seems also to apply to those of C. 
kelungensis. 
No. 120568, Henson No. 1194 (Hakodate, September 19, 1884), is a 
young inale of the year in the hepatic stage (back, remiges, and rec- 
trices having numerous distinct rufous bars), molting directly into the 
typical gray plumage of the adult; while No, 120567, Henson No, 145 
(Hakodate, September 29, 1883), is a young male in the purely gray 
phase, not yet molting. 
Caprimulgus jotaka TrMM. & Sci. (188) 
Three specimens included in the table below. In the young bird the 
upper and lower tail-coverts, as well as a number of feathers on the 
hind neck, belong tothe first plumage. In general coloration Mr. Hen- 
souw’s Yezo birds agree with others in the National Museum from Hondo, 
and with a specimen collected by Petersen in Kiusiu. 
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