specimens of both the northern and southern forms, finds the differences so slight and the individual variations so frequent that he cannot support Mr. Gätke's views. Should such a difference, however, be found to exist, he informs me that the Norfolk-killed bird would certainly belong to the Siberian form.
"It frequents pine-woods, and those of mixed pine and birch in hilly districts, sometimes ranging in the mountains as high as the border of tree-growth, and it is also met with in the beech-covered valleys." The call-note is said by various authorities to be seldom repeated, and to be rendered as tsii, very different from that of P. superciliosus; and the song of the male, which is continued for hours without intermission, is described as melodious, varied, and sweet, and "so loud that it rings through the forest, and is astonishing as coming from so small a bird." The nests are placed on the branches of pines or cedars, either near the outer end or where the junction of the bough with the stem takes place; they are neatly constructed of the materials at hand, such as grass-bents, moss, and lichens, partially domed and lined with feathers and hair. The eggs, which are produced from late in May in the southern localities to the middle of June in Eastern Siberia, are five in number, pure white, richly marked with dark brownish-red and deep purple-grey spots, chiefly at the larger end; and the female is said to "commence sitting directly the first egg is laid, so that in the same clutch one finds quite fresh as well as incubated eggs" (Dresser, 'Birds of Europe,' Supplement, ii. p. 76).
In my previous notice of the occurrence of this bird, in the December number of 'The Zoologist,' p. 467, I remarked that this species may be distinguished from P. superciliosus by "the pale mesial line on the crown." I should have stated that this "mesial line" in P. superciliosus is much paler than in P. proregulus, and that in females and young birds, according to Mr. Gätke, there is not even a trace of it. The most conspicuous difference, however, is the pale yellow colour of the rump in the latter species.
