In this nest, which measured five and three quarters inches by five in breadth, the size, solidity, and strength, in view of the diminutive proportions of its tiny architect, are quite remarkable. The walls were two inches in thickness and very strongly impacted and interwoven. The cavity was an inch and a quarter wide and four inches deep. Its hemlock framework had been made of green materials, and their strong and agreeable odor pervaded the structure. The eggs measured .65 by .48 of an inch, and were spotted with a bright reddish-brown and a few pale markings of purplish-slate, on a pure white ground. Compared with the eggs of the European Wren their eggs are larger, less oval in shape, and the spots much more marked in their character and distinctness. Troglodytes parvulus, var. alascensis, BAIRD. ALASKA WREN. _Troglodytes alascensis_, BAIRD, Trans. Chicago Acad. Sc. I, ii, 315, pl. xxx, fig. 3, 1869.—DALL & BANNISTER (Alaska).—FRIESCH, Ornith. N. W. Amerikas, 1872, 30. SP. CHAR. ♂ ad., 61,329, Amaknak Island, Unalaschka, Oct. 21, 1871; W. H. Dall. Above umber-brown, more rufescent on the wings, rump, and tail; secondaries and tail-feathers showing indistinct transverse dusky bars; primaries about equally barred with blackish and dilute umber or brownish-white; middle-coverts tipped with a small white dot, preceded by a black one. Lower part, including a rather distinct superciliary stripe, pale ochraceous-umber; sides, flanks, abdomen, and crissum distinctly barred with dusky and whitish on a rusty ground; crissum with sagittate spots of white. Wing, 2.20; tail, 1.60; culmen, .65; tarsus, .75. HAB. Aleutian and Pribylow Islands, Alaska. The specimen above described represents about the average of a large series obtained on Amaknak Island by Mr. Dall. They vary somewhat among themselves as regards dimensions, but all are very much larger than any specimens of _T. hyemalis_, from which it also differs in longer, straighter, and more subulate bill (the gonys slightly ascending). The type specimen from St. George’s Island was immature, and we embrace the opportunity of giving the description of an adult sent down with several others in the autumn of 1871 by Mr. Dall from Unalaschka. This form bears the same relation to _T. hyemalis_ that _Melospiza unalaschkensis_ does to _M. melodia_; _T. pacificus_, like _M. rufina_, being an intermediate form. HABITS. Of this new variety, the Alaska Wren, but little is as yet known as to its personal history. Mr. Dall states that it is found in abundance all the year round on St. George’s Island, and that it breeds in May, building a nest of moss in the crevices of the rocks, and, according to the Aleuts, lays six eggs. Mr. Dall subsequently found it quite common at Unalaschka in the summer of 1871. GENUS CISTOTHORUS, CABAN.