11 [Vol. xlii. 



The wings, tail, and major coverts are not replaced in this 

 plumage — that is, they are retained until replaced by those o£ 

 the adult. I£ I am right in my idea that the head and neck 

 feathers belong to the mesoptile series, then the hemiptile 

 plumage on these parts is apparently suppressed. The 

 mesoptile head is the only part of the plumage in which the 

 sexes differ : in the male the feathers are yellowish with 

 black bars ; in the female the feathers have black central 

 streaks ending in a spot. 



Description of hemiptile plumage. Sexes dissimilar. 



Male. Upper parts olivaceous with dark and yellowish 

 bars towards the tips, some mantle and scapular feathers 

 darker and with broad yellowish tips. Chin, throat, and 

 ear-coverts to behind e} e pale isabelline ; breast isabelline 

 with crescentic brown markings ; black pectoral line of 

 adult indicated ; belly blackish in the middle, rufescent at 

 the sides. 



Female. General appearance is like the adult female 

 above. The yellow and black barring is bolder and wider 

 than in the mesoptile dress, and lacks the very large terminal 

 yellow spots of the adult. The breast is like that of the 

 adult, but the dark markings are round or broad crescents, 

 not definite bars with terminal spots and central streaks as 

 in the adult. The breast-feathers are quite different to those 

 in the mesoptile plumage. The belly is apparently blacky 

 not rufous and black bars as in the adult. Further speci- 

 mens, however, are required to work this plumage out in 

 full detail. 



(4) Adult or teleoptile plumage. Acquired by complete 

 moult. 



It will be noticed that these plumages of Sand-Grouse 

 differ from that which obtains in Game-birds, on the one 

 hand^ and Pigeons, on the other, in having both the mesoptile 

 and hemiptile plumages well marked. I do not know any 

 other genus which shows all these plumages in the course of 

 the first six months of life, unless it be, as Mr. Bonhote has 

 recorded, in Bubo and the Game-birds, to which therefore 

 the Sand-Grouse show some relationship. 



