The members of the genus _Erythrodryas_ are much more delicate in structure than the _Petroïcæ_, have their feeble bill strongly beset with bristles, and are more arboreal in their habits; their usual places of resort being the innermost recesses of the forest, where, in a state of quiet seclusion, they flit about in search of insects; the true _Petroïcæ_, on the other hand, frequent open plains, are more bold and vigorous, and possess a structure which adapts them for the ground over which they pass like the _Saxicolæ_. The two species of this genus, all that are at present known, are confined to the south-eastern portions of Australia and Van Diemen’s Land. 154. Erythrodryas rhodinogaster Vol. II. Pl. 1. 155. Erythrodryas rosea, _Gould_ Vol. II. Pl. 2. Genus PETROÏCA, _Swains._ The birds I have retained in this genus might with propriety be divided by separating the pied Robins from the red-breasted species. The dusky Robin of Van Diemen’s Land and the white eyebrowed Robin of the north-east coast of Australia would also constitute another group of equal value with _Erythrodryas_, _Drymodes_ and _Eöpsaltria_. The red-breasted _Petroïcæ_ are confined to the south-eastern portions of Australia, Van Diemen’s Land and Norfolk Island; but I believe that the range of the pied birds extends to New Guinea. Each of the sections I have indicated present some difference in their nidification and in the colouring of their eggs, which tends to confirm the propriety of the view I have taken of the subject. 156. Petroïca multicolor Vol. II. Pl. 3. 157. Petroïca erythrogastra Vol. II. Pl. 4. 158. Petroïca Goodenovii Vol. II. Pl. 5. 159. Petroïca phœnicea, _Gould_ Vol. II. Pl. 6. _Muscicapa erythrogaster_, var. Lath. Gen. Hist. vol. vi. p. 217. 160. Petroïca bicolor, _Swains._ Vol. II. Pl. 7. 161. Petroïca fusca, _Gould_ Vol. II. Pl. 8. _Muscicapa vittata_, Quoy et Gaim. Voy. de l’Astrolabe, pl. 3, fig. 2? 162. Petroïca superciliosa, _Gould_ Vol. II. Pl. 9. Genus DRYMODES, _Gould_. Generic characters. _Bill_ straight, rather compressed on the sides near the tip, nearly as long as the head; a slight notch at the tip; beset at the base with a few fine bristles; _wings_ moderately long, rounded, the first quill very short, the fifth the longest; _tail_ rather long, slightly rounded; _tarsi_ long, slender, entire before; _toes_ moderately long, the outer toe rather longer than the inner; the hind-toe and nail shorter than the middle toe and nail.