Mr. R. Swinhoe on Formosan Ornithology. 299 
bases and the laterals for a great part of their length being 
white. , Under-parts deep bluish grey, striated and mottled 
with white. As the bird gets older, the mottling and white wing- 
spots disappear and the white on the tail contracts. It is in this 
young plumage the R. lineoventris, Hodgs. 
The female, I believe, always carries a partially immature 
plumage. She is usually of a dingy smoke-grey, rather bluer 
on the upper parts. Chin whitish. The under-plumage more 
or less obscurely mottled. Vent, basal half of lateral rectrices 
and a greater or less portion of all the others, and a narrow band 
on the upper tail-coverts white. Rest of tail sepia. Wings the 
same, margined paler. 
60. Ruticilla aurorea (Pall.). 
A few of these may be seen in the low country in winter. 
61. Drymceca extensicauda, Swinhoe, Ibis, 1860, p. 50. 
I have a series of this species both from South and North 
Formosa. They are undistinguishable from the South-China 
bird, except in being rather larger, and having usually more 
robust bills. The bill in this bird, which is light in winter, 
becomes almost entirely black in the breeding-season. 
They are found throughout all the low country of Formosa, 
affecting places covered with coarse long grass, about the tops of 
which they flit and twitter, throwing their tails up and from 
side to side as they spring up the long grass-blade. Their song 
is merely a quick repetition of their usual twittering call-note. 
They feed on small Dipterous caterpillars and other insects. 
Their nests are very elegant little pieces of workmanship, con¬ 
sisting of a deep cup with a canopy, entirely composed of fine 
grass. When first made they are quite green, and elude well 
the eye of search as they stand sustained between the stems of 
long grasses. The bird lays from three to seven eggs of a light 
greenish blue, spotted, blotched, and waved, chiefly at the larger 
end, with various shades of chocolate-brown. They average 
•55 by ’48, but vary in size and shape, and the distribution of 
the chocolate markings assumes all manner of fanciful forms. I 
have a very large series, and they are, I think, the prettiest eggs 
I have ever seen. 
