58 BULLETIN 133, UNITED STATES NATIONAL MUSEUM 



plumes is prohibited. In the Chaco, however, where the aborigines 

 live almost entirely by the chase, Indians are permitted to kill herons 

 and other birds for food at any season, a concession that has led to 

 organized hunting of herons for plumes. In August, 1920, when 

 I was at the Riacho Pilaga in Formosa, the Tobas were preparing 

 for an extended plume hunt in heron rookeries located somewhere 

 near the Rio Pilcomayo and wished me to accompany them. When 

 I inquired concerning the condition of the plumes at that season I 

 found the Tobas well versed in the matter, as they remarked with- 

 out hesitation that eggs should now be hatching in the nests so that 

 in a few days the plumes would be ripe. I was informed that during 

 the previous year Cacique Mavordomo, chief of the Tobas of that 

 section, had organized plume hunting on a cooperative scale, and 

 had secured 78 kilograms of plumes. These had been sold to travel- 

 ing merchants for between 8,000 and 9,000 pesos (at normal exchange 

 9,000 paper pesos is equivalent to about $3,965) for shipment to 

 Buenos Aires. 



ARDEA COCCI Linnaeus 



Ardea cocoi Linnaeus, Syst. Nat., ed. 12, vol. 1, 1766, p. 237. (Cayenne.) 



This heron was observed in fair numbers, but no specimens were 

 secured. The cocoi heron, when seen in the field, resembles the great 

 blue heron of North America in haunt and habits, as it does in call 

 notes and general appearance. It was observed solitary on the shores 

 of large lagoons and rivers, and was more common in the northern 

 portion of the section traversed than in the Pampas. It was recorded 

 in small numbers along the Parana and Paraguay Rivers from Cor- 

 rientes to Puerto Pinasco, from July to September, 1920. About the 

 1st of October adult birds suddenly increased in number along the 

 Rio Paraguay, and many were observed in passing by steamer from 

 Puerto Pinasco to Villa Concepcion on October 2. It is probable 

 that at this time they had come out from the drying Chaco to feed 

 and secure food for young. At Lavalle, Buenos Aires, the species 

 was recorded from November 8 to 16, and at General Roca, Rio 

 Negro, on November 27. Young birds of the year were observed at 

 San Vicente, Rocha, on January 31 and February 2, 1921, and near 

 Lazcano, Rocha, from February 5 to 9. Cocoi herons were noted at 

 Guamini, Buenos Aires, on March 6 and 7, and in the vicinity of 

 Tunuyan, Mendoza, on March 23. 



TIGRISOMA MARMORATUM (Vieillot) 



Ardea marmorata Vieillot, Nouv. Diet. Hist. Nat., vol. 14, 1817, p. 415. 

 (Paraguay.) 



An adult female, taken at Kilometer 80, west of Puerto Pinasco, 

 Paraguay, on September 17, 1920, measures (in millimeters) as fol- 

 lows: Wing, 330; tail, 127.5; exposed culmen, 100; tarsus, 107. A 



