338 Zoological N. Y. Zoological Society. [I; 18 



Cassidix oryzivora mexicana (?) (Less.). Mexican Rice 



Grackle. 



Cassidix oi^yzivora is a rare species in Costa Rica, there 

 being but two authentic records of its occurrence, and one of 

 these is rather obscure.^ There is some doubt as to the form 

 to which Costa Rican specimens should be referred, so mexicana 

 is used advisedly. 



On April 26th, while examining , nests of Zarhynchus 

 luagleri wagleri, one was found containing two young birds 

 about two weeks old. One differed markedly from the other, 

 and proved to be a Cassidix. 



Dr. Emil A. Goeldi^ has described the parasitic habits of 

 C. oryzivora oryzivora of Brazil, which deposits its eggs in the 

 nests of Cacicus persicus, which is the common Cacique there. 

 Zarhynchus is the only Cacique nesting in colonies in the higher 

 parts of Costa Rica, and it is not remarkable that Cassidix 

 should adopt this species for rearing its young. 



The feathers of the young bird were quite black, the legs 

 and feet also black, iris dark hazel. The beak and bare por- 

 tions of the face, including the lores, space in front of the eyes 

 and base of the beak, which were bare of feathers, entirely 

 white. The gape was pale yellow. The bird exhibited the 

 greedy habits usual in parasites and soon was able to care for 

 itself and was brought safely to the Zoological Park. 



On May 25th, faint signs of dark coloring were observed 

 in the beak. These gradually increased, so that the change to 

 the pure black of the adult was seen to be under way. The chief 

 points of color increase were at each side of base and tip of 

 both mandibles, although the patches were very irregular. 



On June 25, it was noted that the anterior portions of the 

 face and the lores were covered with pin-feathers, which 

 soon clothed these parts. The bill was now much darker, the 

 white tracts being greatly restricted. By August 10, the change 

 was practically complete, only faint traces of white at the tip 

 of the upper mandible remaining. 



It is not possible to determine the particular subspecies to 

 which this bird is referable until it becomes adult. 



1 Cairiker. Lisl, of Hip Birds of Costa Rica, p. 832. 



2 Ibis, Vol. ]IT. Ninth S.-ries. 1897, pi). ?.C,1-?,G5. 



