248 Proceedings of the Royal Physical Society. 



Gibson mentions having seen it among the reeds in the 

 swamps. It is a voluminous structure, about three times the 

 size of a sparrow. That sent with the above clutch is of a 

 domed-shape, with an opening in the side, and formed of wool, 

 hair, and feathers. The eggs are usually four in number, and 

 never more than five. 



17. Serpophaga nigricans (Viell.) — native name ''Eatoncito." 

 — This species is generally found at Tala, in thickets of willow 

 and other trees near the river. It is resident. It approaches 

 the titmice in habits, but generally frequents lakes, ditches, 

 and other moist places. In the Argentine Eepublic it is found 

 on the shores of the river Plate, among dense cover, where it 

 often alights on aquatic plants, growing in the water. When 

 seated on a twig, it is fond of expanding its tail like a fan. 

 They move generally in parties of three or four together. 



Clutch of two eggs, taken 8th November 1879, from a nest 

 placed on the banks of the Tala Kiver. These measure -rJ x ij 

 inch, are pyriform, and of a yellowish white, unspotted (PI. 

 VIIL, fig. 3). 



It is said to lay only two eggs. The nest is about two 

 inches in diameter, across the opening, is cup-shaped, and 

 formed of moss, dry grass, and hair, felted together like that 

 of a greenfinch, and warmly lined with feathers, chiefly those 

 of the partridge {N. maculosa). 



18. Milvulns tyrannus (L.) — Scissor Bird : native name 

 " Tejerito." — A common species in Mexico, and throughout 

 the whole of South America, to the Straits of Magellan. At 

 Tala it is migratory, and not very common, nor so numerous 

 as in the Argentine Eepublic, where it is also migratory, 

 passing on to Patagonia. Its habits resemble those of the 

 other flycatchers. It often sits solitary, on the bough of an 

 ombu tree, whence it takes short flights after insects, return- 

 ing to its perch. From the structure of the tail, it has re- 

 ceived the above name from the natives. Like all birds so 

 constructed, it has the power of turning short in its flight, 

 and at the same moment opening and closing its tail, some- 

 times vertically and sometimes horizontally. On the wing it 

 presents a caricature of the common swallow, with its forked 

 tail, while its note also resembles the twittering of that bird. 



