species of the Genus Acrocephalus. 43 



lessness, stated to be identical with the Tahiti bird. I can 

 only plead in excuse that I worked by gaslight, and failed to 

 notice the distinction in coloration. 

 I propose now to describe it as 



2. Acrocephalus mendan^, sp. nov. (Plate I.) 



A. ^ Acrocephalo otatare [Tatare /on^iros^ri) coloribus simil- 

 limus, sed paullo minor, et rostro paullnlum incurvato. 

 Non solum tectricibus alse inferioribus flavis, sed etiam 

 remigum pogonii interni dimidio Isete flavo, ita ut tota 

 ala inferior sit flava, apice bruuneo ; rectricibus externis 

 omnino flavis, secundse et tertise scapo et pogonio interno 

 flavis ; rectricibus omnibus flavo terminatis. Long. tot. 

 8, alse. 3'7, caudse 3'6, rostri a rictu rl5, tarsi 1'05. 

 $ mari similis et vix minor. 

 Habitat. Ins. Marquesas. 



I have named this very distinct species in honour of Men- 

 dana, the adventurous Spanish voyager and discoverer of the 

 Marquesas Islands, its home. 



In coloration and character of plumage it resembles A. 

 otatare, but may be at once distinguished by its much 

 smaller size, by its bill being slightly incurved instead of 

 perfectly straight as in its congener, by the whole under 

 surface of the wings being of a rich lemon-yellow, excepting for 

 the lower third of the outer primaries, Avhile the under wing 

 of the other species is bufly white interiorly and dark brown 

 towards the outside, only the axillaries being lemon-yellow. 

 Lastly, it is distinguishable at a glance by the outer tail- 

 feathers being pure yellow, and the next two pairs being 

 yellow on their inner webs, while the whole tail is broadly 

 tipped with lemon-yellow. In A. otatare the whole tail is 

 brown^ with an indistinct huffy white termination. 



There is also a remarkable difference in the young birds of 

 the two species. Those of the Marquesas bird are coloured 

 in every respect precisely like the adults (and I possess them 

 in two stages), .while, according to the specimens in the 

 Bremen Museum, the young of the Society-Island species 

 are of a uniform veiy dark brown, strangely unlike tiie colo- 

 ration of the adult, and with no trace of yellow in tlicir 



