PTEROCLES ARENARIUS 235 



Descri2)tion.— Adult male, spring, from Hadj-el-Aioum, Central Tunisia. 



Forehead, crown, and nape dove-grey, rather paler round the eye ; back, 

 scapulars, lesser wing-coverts, rump, aud upper tail-coverts blackish-grey, 

 mottled with yellowish-buff, brightsst on the wing-coverts ; greater and 

 median wing-coverts bright orange-buff; primaries slate-grey, with black 

 shafts, the outermost primary with a lilack outer web ; most of the secondaries 

 blate-grey on the inner, and orange-buff on the outer webs ; tail ash-grey, 

 barred with rufous-brown on the basal portion, and tipped with white ; chin 

 and throat rust-colour, with a black patch below, and becoming rufous- 

 orange on the sides of the neck ; upper breast pearl-grey ; lower breast 

 isabelline-buff, the two colours divided by a black pectoral band ; abdomen 

 and sides of body coal-black ; under tail-coverts whitish ; tarsus feathered 

 down to the toes with pale buff. 



Iris almost black ; bill and feet grey. 



Total length 12o0 inches, wing 9, culmeu -50, tarsus 1. 



Adult female, spring, from Oglet-Zelles, South Tunisia. 



Upper plumage pale sandy-buff with a rufescent tinge ; head and nape 

 finely striped with black, the other parts finely Ijarred and vermiculated 

 with black ; primaries greyish-brown ; throat and cheeks tinged with pale 

 yellow, below which is a black stripe ; upper breast pale rufescent- buff", 

 spotted with dark brown ; below that a black pectoral band : lower breast 

 pale unspotted buff ; abdomen and sides of body black ; under tail-coverts 

 white, 



Soft parts and measurements as in the male. 



Observations. — There is a considerable amount of seasonal variation in 

 the plumage of this species, noticeable in both sexes. The spring plumage 

 in both is purer and brighter than the autumn dress. 



This Sand-Grouse is common throiigliout a considerable portion of 

 the Tmiisian llegency, aud particularly in the central and southern 

 districts. North of the Atlas it is less abundant, and apparently not 

 to be found throughout the entire year. 



The true home of the species is undoubtedly the semi-desert 

 country and vast undulating stony plains south of the Atlas, where 

 the general colouring of the soil and environment harmonise so admir- 

 ably with its plumage and help to render it inconspicuous. The same 

 may indeed be said of other species of Sand -Grouse, and there are 

 perhaps few better illustrations of Nature's protective colouring than 

 those afforded by the members of this family. 



Though distinctly a resident species in Tunisia, P. arenarius 

 appears to shift its quarters a good deal and to be in some measure 



