112 A MANUAL OF THE BIBDS OF AUSTRALIA. 



margined with buff ; lesser upper wing-coverts dark brown with earth-brown 

 margins to the feathers ; bastard-wing and primary -coverts uniform pale 

 brown ; primary and secondary flight-quills dark brown on the outer webs, paler 

 on the inner ones which are white at the base, the shafts of the feathers con- 

 spicuously white on the outer primaries, most of the secondaries have pale narrow 

 edges at the tips ; lower back almost uniform ash-brown ; rump and upper tail- 

 coverts barred with white or smoky -white ; tail dark brown, white on the basal 

 portion of the inner webs, the two middle feathers only slightly exceeding the lateral 

 ones in length ; a pale eyebrow slightly indicated ; hinder face isabelline with dark 

 narrow shaft-lines to the feathers ; throat white with pale brown pear-shaped marks 

 on the middle of the feathers, lower throat similar, but tinged with buff ; fore-neck, 

 sides of neck, upper -breast and sides of breast pale brown barred with white or buffy- 

 white like the sides of the body and under tail-coverts ; breast, abdomen and vent 

 white ; under tail-coverts and axillaries pale brown barred with white ; quills below, 

 white at the base and brown on the apical portion like the lower aspect of the tail. 

 Eyes and bill black. Tarsus pale blue-black on the back. Toes and webs black. 

 Total length 475 mm. ; culmen 39, wing 375, tail 155, tarsus 52. 



Immature. General colour above dark brown, the feathers everywhere margined 

 and spotted with ochreous or rufous, more thickly on the rump and upper tail- 

 co verts and more sparsely on the head and hind -neck ; the small coverts round the 

 bend of the wing white with dark centres ; under parts more rufous and barred 

 almost entirely over the whole surface, each feather being white at the base with two 

 brown bars and fringed with rufous, more coarsely on the flanks ; the long under 

 tail-coverts have four brown bars ; under wing-coverts brown barred with white ; 

 axillaries, some uniform grey with twin spots of rufous at the tips, others are greyish- 

 brown barred and irregularly marked with white, fringed also with the same colour 

 at the tips ; a dark spot in front of the eye. 



Nestling in down. Pale sooty-brown above with a tinge of rufous, paler sooty 

 below. 



Nest. None made, the eggs are placed on the moss. 



Eggs. Clutch, two ; the eggs have, on a yellowish -olive ground -colour, a few 

 spots of greyish-brown, irregular and fairly pale, and other overlying spots of a 

 rather deep olive-brown ; others have a pale greenish ground-colour, varied by small 

 pale ashy spots, and olive-brown ones smaller than the former and a little deeper 

 in colour. The surface is fairly rough and a little glossy. Length 61-64 mm., by 

 42-46. 



Breeding-season. July. 



Distribution and forms. Along the Arctic Circle, wintering in the southern 

 hemisphere. An eastern and western form has been admitted, but the Australian 

 specimens are not exactly in agreement, and consequently Mathews proposed the 

 above name until more material is examined and the exact status determined. 



Genus STERCORARIUS. 



Stercorarius Brisson, Ornith., Vol. I., p. 56, Vol. VI., p. 149, 1760. Type (by tautonymy) : 



Stercorarius = Larus parasiticus Linn6. 



Lestris Illiger, Prodr. Mamm. et Av., p. 272, (pref. April) 1811. Type (by subsequent 



designation) : L. parasiticus Linne. 



Prcedatrix Vieillot, Analyse nouv. Ornith., p. 65, April 14th, 1816. Type (by monotypy) : 



Labbe Buffon = Larus parasiticus Linn. 



Oceanus Koch, Syst. baier. Zool., p. 380, (July) 1816. Type (by monotypy) : L. parasitic u." 



Not of Montfort, Conch. Syst., Vol. L, p. 58, 1808. 



Labbus " Rafinq. 1816 " Gray, Cat. Gen. Subgen. Birds, p. 129, Oct. 1855. In synonymy. 

 Atalolestris Mathews, Birds Austr., Vol. II., pt. 5, p. 500, Jan. 31st, 1913. Type (by original 

 designation) : Stercorarius longicaudus Vieillot. 



