16(y MR. P. L. St'LATEK 0>' A RARE ARGENTINE BIRD. [Jail. 17, 



I have mikli hesihition in separating this species from C 

 orieiitalis, Uliaiiin, from which it diiiers chiefly in the proportions 

 of the abdominal segments, in the size of the third free thoracic 

 segment, \\ hich is larger than in C. orientalis, and in the size of the 

 fused head ai;d first thoracic segment, which in C. orientalis is 

 equal in length to the four free thoracic segments and the lirst 

 abdominal segment, while in 0. africanus it is much shorter. I 

 have not been able to find a female carrying ova, but the specimen 

 from which the description is taken had its ovaries full of ripe ova. 



The single male specimen I found was apparently mature. It 

 (hflf'ers markedly in the jointing and in the proportions of the 

 anteniue from Uljanin's figure, which is very probably taken from 

 an immature specimen. 



EXPLANATION OF PLATE VI. 



Canthocamptus finni, p. 1G4. 

 Eig. 1. Lateral view of f'eniaLe. 

 2. First antenua of female, 

 o. Second antenna. 



4. Mandible. 



5. First swimniing-foot. 

 (5. Fourth swimming-foot. 

 7. Fifth foot of female. 



Cyclops africanus. p. IC),''). 

 Fig. 8. Female, viewed from above. 

 ',>. First antenna of female. 



10. First antenna of male. 



11. Fifth foot. 



4. Remarks on a rare Argentine Bird, Xenopsaris albinucha. 

 By P. L. ScLATER, M.A., Ph.D., F.R.S., Secretary to 

 the Society. 



[Received December 22, 1892.] 



(Plate VII.) 



In 1868 our late distinguished Foreign Member, Dr. H. Bur- 

 mcister, of Buenos Ayres, described, in a communication to this 

 ►Society on additions to the Argentine Avifauna, a small Passerine 

 bird of wliich he had obtained specimens in the sedge of the shores 

 of the Eio de la Plata, near Buenos Ayres, under the name of 

 rnc?i>/rJiamj)hus albimtcJia. No specimen accompanied this com- 

 numication, and the subject appears to Jiave been until quite recently 

 overlooked by subsequent writers. Although the title of the paper 

 was given by Mr. Hudson and myself in the Appendi.\ to our 

 'Argentine Ornithology' (op. cit. ii. p. 222), and it is there re- 

 corded that Puclnjrhamphus albinucha was described as new, the 

 species was unfortunately forgotten in the body of that work. The 

 same was the case, I regret to say, in the fourteenth volume of the 



