moderately developed rictal bristles. In two of the species the bill 

 is somewhat aberrant, being as slender as in the genus LocuMdla. 

 These two species are also distinguished by a different style of 

 colouring, each feather on the head and back being darker in the 

 centre. The existence of two other intermediate species makes it, 

 however, advisable not to separate them more than subgeuerically 

 from the typicil Acrocephuli. 



The tail is more rounded than in Hiipolais, and much more so 

 than in Phiillosvopns, but not so much so as in Locustella, the out- 

 side tail-feathers being longer than the under tail-coverts. 



The general colour of the plumage is a more or less uniform 

 brown, sometimes olive-brown, sometimes russet-brown, gradually 

 fading, as the plumage becomes abraded, into a neutral brown or 

 dust-brown, not inaptly described as mus-nim colour. 



ilost of these birds are migratory, anl moult twice in the year, 

 shortly before each journey. Their breeding-range extends over 

 the whole of the central and southern Paifearctic Region, but only 

 one species extends ns far north as the Arctic Circle. They winter 

 in the tropical regions of Africa and Asia, and are especially common 

 in the islands of the Malay archipelago. Two species apparently 

 migrate south instead of north to bieed, and resort to the swamps 

 of Australia for that purpose. Two other species appear to be 

 non-migratory — one having found a permanent home in South 

 Africa, and the other in the Caroline Islands in the Pacific. 



Key to tlie Species. 



A. Crown between the eyebrows with two or 



more dark longitndin il bands. Bill somewhat 

 narrowed at the base, and slender as in Locus- 

 tella, but rictal bristles fairly developed. 



( Subgeneric group CALAiiODi.) 



a. Second primary longer than the fourih. 



a'. Two broad dark longitudinal bands on the 



crown aquaficTts, p. 89. 



b'. Four dark longitudinal band? on the 



crown p/ira(/mitis. p. 91. 



b. Second primary shorter shan the sixth. 



f'. A dark stripe over each eye. Feathers of 



the crown and upper parts generally with 



dark centres sorgophihis, p. 94. 



(V. A dark stripe over each pye, otherwise the 



crown and upper parts urjifonu in colour bistrigiceps, p. 94. 



B. Crown between the eyebrows uniform in 



colour. Bill wide at the base, and more robust 

 thiin in Locustella; rictal bristles fairly de- 

 veloped. (Subgeneric group Acbocephali.) 



c. Length of wing from 3'9 to 2-7 inches; if 



under .3 inches, second primary equal to or 



shorter than the fifth. 



e'. Length of wing 3-9 to 3'6 inches. Second 



primary equal to the third, or between 



the third and fourth. Legs and feet pale 



brown turdoides, p. 95. 



