INSESSORES. 275 



branches of the trees, it is not easily procured, its diminutive 

 size preventing its being seen. 



There is no outward difference in the sexes, either in size 

 or plumage. Future research, and a longer sojom'n in the 

 country than has hitherto been afforded for the investigation 

 of the natural productions of those distant parts, are requisite 

 to determine whether it be migratory or not, and to procure 

 correct information respecting its nidification. 



All the upper surface bright yellowish olive ; the feathers 

 of the head with an indistinct line of brown down the centre ; 

 wings brown ; tail brown, deepening into black near the ex- 

 tremity, and with a large oval spot of white on the inner 

 web near the tip of all but the two central feathers ; all the 

 under surface bright yellow. 



Total length 2f inches ; bill ^ ; wing -^ ; tail 1 J ; tarsi -i%. 



Tamily SAXICOLID^. 

 Genus ERYTHRODRYAS, Gould. 



The birds of this form are much more delicate in structure 

 than the members of the restricted genus Petroica, have their 

 feeble bill strongly beset with bristles, and are more arboreal 

 in their habits ; their usual places of resort being the inner- 

 most recesses of the forest, where, in a state of quiet seclusion, 

 they flit about in search of insects ; the true PefroicfB, 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 Wheatears. 



The two species of this genus, all that are at present 

 known, are confined to the south-eastern portions of Australia 

 and Tasmania. 



We may naturally conclude that, in their mode of nidifica- 

 tion, the form of their nests, and in the number and colour of 

 their eggs, they will very closely resemble the true Petroica. 



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