Azara says:--"I give it this name because it sings it plainly, in a loud sharp tone, which may be heard at a distance, repeating it so frequently that the pauses last no longer than the sound. It is resident (in Paraguay), solitary and not abundant: inhabits thickets of aloes and thorn, without rising more than two yards above the surface, or showing itself in open places. It moves about incessantly, but does not leave its thicket to visit the woods or open ground, its flight being only from bush to bush; and though it is not timid, it is hard to detect it in its stronghold, and to hear it one would imagine that it was perched overhead on a tree, when it is hidden all the time in the brushwood at the roots." This habit of concealing itself so closely inclines me to think that this species, rather than _S. albescens_, was the bird described by Azara, although in both species the language is nearly the same. I have nothing to add to the above account from the 'Apuntamientos,' except that in the love-season this species has a low, strange-sounding little song, utterly unlike its usual strident cry. When singing, it sits motionless on the summit of a low bush in a dejected attitude with head drawn in, and murmurs its mysterious little melody at intervals of half a minute. 194. SYNALLAXIS ALBESCENS, Temm. (WHITE-THROATED SPINE-TAIL.) +Synallaxis albescens+, _Scl. et Salv. Nomencl._ p. 63; _Scl. P. Z. S._ 1874, p. 9; _Durnford, Ibis_, 1877, p. 180 (Buenos Ayres); _White, P. Z. S._ 1882, p. 611 (Misiones); _Barrows, Bull. Nutt. Orn. Cl._ viii. p. 207 (Entrerios). _Description._--Above, forehead grey, crown pale chestnut; sides of head and neck, back, and tail pale earthy brown; upper wing-coverts pale chestnut, wing-feathers olive-brown; beneath white, faintly washed with earthy brown; under wing-coverts fulvous: whole length 5·3 inches, wing 2·0, tail 2·2. _Hab._ S. America, from Veragua to Buenos Ayres. This species, although by no means abundant in Buenos Ayres, is met with much more frequently than the _S. spixi_, which it closely resembles in size, colour, habits, and language. It is, indeed, an unusual thing for two species so closely allied to be found inhabiting the same district. In both birds the colours are arranged in precisely the same way; but the chestnut tint on _S. albescens_ is not nearly so deep, the browns and greys are paler, and there is less black on the throat.