238 • BIRDS OF TUNISIA 



PTEROCLES ALCHATA (Linnjeus). 

 PIN-TAILED SAND-GKOUSE. 



Tetrao alchata, Linn. Syst. Nat. i, p. 276 (1766). 



Pterocles alchata, Temm. Man. d'Orn. p. 302 (1815); Kocnig, J.f. 0. 



1893, p. 71 : Whital-cr, Ibis, 1895, p. 105 ; Erlangcr, J. f. 0. 1900, 



p. 34. 

 Pterocles setarius, Malhcrbc, Cat. Bais d'Ois. Alcj. p. 18 (1846). 

 Pteroclurus alchata, Loche, Expl. Sci. Alg. Ois. ii, p. 232 (1867) ; 



Ogihie-Granl, Cat. Birds Brit. Miis. sxii, p. 7. 



Description. — Adult male, spring, from Ain-el-Ksob, Central Tunisia. 



Forehead and sides of head dark gamboge-yellow ; a narrow black stripe 

 extending from the eye backward ; crown greenish-grey ; nape dull greenish ; 

 back and scapulars brownish green, some of the feathers tipped with large 

 yellow spots ; rump and upper tail-coverts yellow, closely barred with 

 black ; the two central rectrices, which are much elongated, dark brown, 

 the remainder tipped with white ; primaries grey, with black shafts and 

 brown inner webs, e.^cept the outermost feather, which is black on the outer 

 web ; upper wing-ooverts brown on the outer portion and on the shoulder, 

 below which is a large patch of rufous-browu, fringed with narrow lines of 

 black and white, and lower still are some grey and black feathers ; inner 

 wing-coverts and secondaries greenish like the scapulars ; chin and centre 

 of the throat black, bordered with gamboge-yellow ; fore neck dull golden- 

 green ; breast light cinnamon, with black pectoral l)ands above and below ; 

 remainder of the underparts white. 



Iris almost black ; bill and feet grey. 



Total length 12-50 inches, wing 8-50, culmen -50, tarsus 1. 



Adult female, spring, from Bir-Sliman, South Tunisia. 



Forehead, crown and nape yellowish-buff, closely barred with black, 

 and with a black stripe extending from the eye backward ; remainder of 

 upper plumage generally yellowish- buff with a rutescent tinge, and closely 

 baiTed and pencilled with black, brown and pearl blue ; quills grey ; tail as 

 in the male ; chin and centre of throat white ; lower throat, sides of head 

 and neck yellowish-buff, with two black collar bands, below which the 

 breast is pale cinnamon, followed by a third black pectoral band ; rest of 

 the underparts white. 



Soft parts and measurements as in the male. 



Observations. — For the remai'kable seasonable changes in the male of 

 this species, cf. Grant, Game Birds, i, p. 8. 



The chief difference between typical P. alchata, and the Spanish form 

 P. a. pyrenaicus (Briss.) is that in the male the subniarginal fringe on the 

 chestnut wing-coverts is ivhitc in the former and yellow in the latter, while 

 in the female these wing-coverts are generally lighter in the former and 

 darker in the latter. 



