Mr. Barrows has the following very interesting note on its nesting-habits:--"A nest containing four white eggs, faintly tinted with blue, was found in a thorny tree, and some eight feet from the ground. The nest was quite similar to the one just described (of _S. albescens_), but the cavity in which the eggs were laid was near the _top_ of the body of the nest, while the passage-way descended from it to the base of the nest, and there becoming external rose gradually to the level of the eggs at a distance of almost three feet." 197. SYNALLAXIS STRIATICEPS (Lafr. et d'Orb.). (STRIPED SPINE-TAIL.) +Synallaxis striaticeps+, _Burm. La-Plata Reise_, ii. p. 469 (Paraná); _Hudson, P. Z. S._ 1872, p. 544 (Rio Negro); _Scl. et Salv. Nomencl._ p. 64; _Scl. P. Z. S._ 1874, p. 21; _Salvin, Ibis_, 1880, p. 358 (Salta); _White, P. Z. S._ 1883, p. 39 (Cordova); _Barrows, Bull. Nutt. Orn. Cl._ viii. p. 208 (Entrerios). _Description._--Above earthy brown, darker on the crown, which has slight greyish striations; broad superciliaries white; upper wing-coverts pale chestnut; wing-feathers blackish, glossed with olive; tail pale chestnut; beneath white; under wing-coverts pale fulvous; bill and feet horn-colour: whole length 5·9 inches, wing 2·4, tail 2·4. _Female_ similar. _Hab._ Bolivia, Argentina, Uruguay, and Patagonia. This species has a wide range south of the Equator, being found in Bolivia, Uruguay, and throughout the Argentine Republic, including Patagonia. In its habits it differs widely from other _Synallaxes_, and in structure and coloration is also unlike its relatives. The beak is longer and more curved, the claws more crooked, and the tail stiffer than in other _Synallaxes_, and this difference in structure corresponds to a different mode of life. The Striped Spine-tail creeps on the trunk and larger branches of trees, seeking its insect-food in the crevices of the bark, and when seen clinging to the trunk, supported by its tail in a vertical position, with head thrown far back, and progressing upwards by short quick hops, it looks wonderfully like a small _Picolaptes_ with shortened beak. It is very restless, and while searching for insects constantly utters a short, trilling, querulous-sounding note. It builds an open nest in the fork of a branch, of soft grasses and hair, thickly lined with feathers, and lays four or five pure white eggs. 198. SYNALLAXIS ORBIGNII, Reichenb. (D'ORBIGNY'S SPINE-TAIL.) +Synallaxis orbignii+, _Scl. et Salv. Nomencl._ p. 64; _Scl. P. Z. S._ 1874, p. 22, et 1879, p. 461; _Salvin, Ibis_, 1880, p. 358 (Salta). +Synallaxis humicola+, _Burm. La-Plata Reise_, ii. p. 468 (Mendoza, Paraná). +Synallaxis crassirostris+, _Leybold, J. f. O._ 1865, p. 401. +Synallaxis flavigularis+, _Döring, Exp. al Rio Negro, Zool._ p. 45.