3. BUTEO VENTRALIS. _Gould._ Buteo ventralis, _Gould_, Proceedings of the Zoological Society, Part v. 1837, p. 10. _B. vertice corporeque intensè nitide fuscis, plumis dorsalibus purpurascentibus; primariis nigris; caudâ fuscâ, lineis obscurioribus cancellatâ numerosis, ad apicem sordidè albâ; gulâ abdomine medio crissoque stramineo-albis; pectoris corporisque lateribus fasciâ abdominali femoribusque flavescenti-albis fusco notatis, notis in femoribus rufescentibus; tarsis per mediam partem anticè plumosis, rostro nigro; cerâ tarsisque flavis._ Long. tot. 23 unc.; _alæ_, 15½; _caudæ_, 9½; _tarsi_, 3½. COLOUR.—Head, back of neck, back, and wing-coverts, umber brown. Feathers on sides of throat edged with fulvous; those on lower parts of back with their basal parts marked with large white spots, edged with fulvous, but which do not show, until the feathers are ruffled. Tail of the same dark brown as the back, with many bars of pale brown, and extreme points tipped with dirty white. Tail-coverts same brown, with the more lateral ones marked with white and fulvous. Wings: primaries black, with the inner and basal webs brownish; secondaries and tertiaries brown, with obscure traces of paler transverse bars. _Under surface._—Chin almost white; throat and breast very pale ochre yellow, with narrow brown lines on the shaft of the feathers, which expand into large marks on the sides of the upper part of the breast, and into regular spots on those of the belly. Lining of wing white, with brown spots on the feathers near their tips, like on those of the belly. Thighs very pale ochre yellow, with transverse bars of pale brown, appearing like inverted wedge-formed marks, with the apex on the shafts. Under tail-coverts almost white; under side of tail pale gray, with darker gray bars on the inner side of shafts. Bill blueish black, with base of lower mandible and part of upper yellowish. Tarsi pale yellow. FORM.—Fourth primary very little longer than either the third or fifth, which are equal. First nearly equal to the eighth. Extremity of wing when folded reaching within two inches and a half of the end of the tail. In. Total length 23 Wing when folded 15½ Tail 9½ Tarsi 3½ Middle toe from joint to tip of claw 3 From extremity of beak to within nostril ⁹⁄₁₀ Habitat, Santa Cruz, Lat. 50° S. Patagonia, (_April_.)