incubate by turns, and when one returns from the feeding-ground it sings its loud notes, on which the sitting bird rushes forth to join in the joyous chorus, and then flies away, the other taking its place on the eggs. The young are exceedingly garrulous, and when only half-fledged may be heard practising trills and duets in their secure oven, in shrill tremulous voices, which change to the usual hunger-cry of young birds when the parent enters with food. After leaving the nest, the old and young birds live for two or three months together, only one brood being raised in each year. A new oven is built every year, and I have more than once seen a second oven built on the top of the first, when this has been placed very advantageously, as on a projection and against a wall. A very curious thing occurred at the estancia house of a neighbour of mine in Buenos Ayres one spring. A pair of Oven-birds built their oven on a beam-end projecting from the wall of a rancho. One morning one of the birds was found caught in a steel trap placed the evening before for rats, and both of its legs were crushed above the knee. On being liberated it flew up to and entered the oven, where it bled to death, no doubt, for it did not come out again. Its mate remained two days, calling incessantly, but there were no other birds of its kind in the place, and it eventually disappeared. Three days later it returned with a new mate, and immediately the two birds began carrying pellets of mud to the oven, with which they plastered up the entrance. Afterwards they built a second oven, using the sepulchre of the dead bird for its foundation, and here they reared their young. My neighbour, an old native, had watched the birds from the time the first oven was begun, feeling greatly interested in their diligent ways, and thinking their presence at his house a good omen; and it was not strange that, after witnessing the entombment of one that died, he was more convinced than ever that the little House-builders are "pious birds." 179. FURNARIUS TRICOLOR, Cab. (CRESTED OVEN-BIRD.) +Furnarius tricolor+, _Cab. Journ. f. Orn._ 1878, p. 196 (Cordova). +Furnarius figulus+, _White, P. Z. S._ 1882, p. 609 (?). _Description._--Above nearly uniform earthy brown, head slightly crested; tail bright ferruginous; beneath paler, throat pure white; middle of belly and crissum white; under surface of wings blackish, with a transverse bar of pale cinnamon; bill hazel, paler at the base; feet blackish: whole length 5·7 inches, wing 2·8, tail 2·2. _Hab._ Cordova. This pretty little species is a recent discovery of Döring in the Sierras of Cordova; it may be at once recognized by its small size and crested head. 180. UPUCERTHIA DUMETORIA (Geoffr. et d'Orb.). (PATAGONIAN EARTH-CREEPER.)