Nesting of Cassicus persicus^ i^c. 303 



Oslinops decuinauHS aud Cassicus hceuwrrhous. TUlandsiu' 

 threads are softer aud of a greyish colour, while fihres 

 of assay-leaves are more rigid and of a straw-colour — so that 

 Cassicus-nests of unknown origin may be at any time 

 certainly recognized, by their materials as to whether they 

 come from the southern or from the northern parts of Brazil. 

 The life and growth of these Tillandsia-fihres are not always 

 interrupted by their employment in the nests. I have often 

 observed instances of these Bromelias growing under such 

 circumstances. 



The eggs of Cassicus peisicus were not obtained by Prince 

 zu Wied. Whether they have been more recently procured 

 I am not able to say from the literature at my disposal. They 

 are of a very pale yellow-reddish colour, almost regularly 

 covered with pale neutral-tint signs and points in two layers of 

 different intensity. The measurements of two Guianan eggs 

 are : — (1) Long, axis 25*5 mm., transv. axis 19 mm. ; (2) long, 

 axis 27'5 mm., transv. axis 18 mm. 



In a letter dated Sept. 12th, 1896, Mr. Sclater writes to 

 me : — " We have been recently informed that Cassidix oryzi- 

 vora is parasitic on Cassicus persicus — like Molothrus. Do 

 you know anything about this matter? '' Now I really know 

 something about this question, and have even published, 

 some remarks concerning it some years ago"^. 



In Southern Brazil it is well known that Molothrus boiia- 

 riensis lays its eggs in the nests of other birds, especially in 

 that of Zonotrichia pileata. Its larger relative (^Cassidix 

 oryzivora) lays its eggs in the nests of birds of similar 

 proportions to itself, especially in those of Ostinops decu- 

 manus, and probably also in those of Cassicus hcemorrhous. 

 As regards Ostinops, there is absolutely no doubt; I have 



* In ruy little book ' Aves do Brazil ' (Rio de Janeiro), written in 1892 

 aud printed in 1894 — a book which has been condemned by ' Natural 

 Science ' as " being of no value as a contribution to science." If, 

 however, the editors of that periodical would give themselves the trouble 

 to study it a little more from the biological standpoint, and not merely 

 through anatomical and systematical spectacles, they would, perhaps, be 

 able to record a somewhat more favourable opinion of it. — E. A. G. 



2c2 



