140 Barrows 071 Birds of the Lower Uruguay. [J"ly 



eggs were sometimes spotted. The sexes are precisely alike in 

 color, and the young when able to fly differ but slightly in ap- 

 pearance from the parents. From the fact that young unable to 

 fly were taken in November, I judge that a second brood is not 

 infrequently raised. The adults have several of the first pri- 

 maries remarkably attenuate. Young birds appear to acquire 

 these attenuate primaries only after a complete moult. But I 

 took one specimen which showed one or more primaries with 

 tips of ordinary shape but with a line apparently U'cr^ into the 

 vane of the inner web so as to mark out distinctly the attenuate 

 tip, and it seemed as if a little more wearing w^ould cut out a 

 piece which would leave the primary as in the old bird. 



53. Myiotheretes rufiventris {VieilL). — The largest of 

 the family found at Concepcion, where it occurs only in winter. 

 It is found in flocks, the individuals of which scatter about the 

 ground and resemble our common Robins not a little. I have never 

 seen this species alight on a bush or tree, — but as it is not plenty 

 at Concepcion, and as there were no trees or bushes in the region 

 where it was abundant further south, I will not say that it does 

 not often do so. . 



54. Alectorurus guira-yetapa ( PV^///.). Tijerita real 

 (Royal Scissor-tail). — Only sparingly found at Concepcion, 

 and only during warm weather, when it probably breeds. The 

 remarkable condition of the outer pair of tail feathers is interest- 

 ing. In the male these two feathers reach a length of nearly 

 ten inches, the rest of the tail being about three inches in length. 

 The vane on the inner side of each is wanting for the first two 

 inches and then suddenly develops to a width of nearly two 

 inches, which it maintains almost to the tip when it gradually 

 narrows. The vane on the outer side of the shaft is only about 

 one-quarter of an inch wide, and is folded so tightly against the 

 shaft that it is quite inconspicuous. In the only two males of 

 this species which I have seen flying, these long feathers seemed 

 to be carried folded together beneath the rest of the tail, and 

 stretching out behind like a rudder or steering-oar, their vanes 

 at right-angles to the plane of the rest of the tail. The only male 

 which I took myself was shot at Carhu^, April 6, 1881, and had 

 not quite completed the summer moult. The chin, throat, and 

 sides of head below the eyes were completely feathered. Two 

 males, ho"wever, were brought to me at Concepcion, October 7, 



