364 MS. B. SPRUCE ON INSECT-MI&RATIOKS IN SOUTH AMERICA. 



supposed by ttie inhabitants to have some mysterious connexion 

 with the Christian festivals. Thus there are two beautiful little 

 birds in Maynas, apparently belonging to different genera, for one 

 of them is a Seven-coloured Tanager (Pajaro de siete color es), and 

 the other (which I have not seen) is said to be of a bright blue 

 colour and differently shaped ; but both are called by the Indians 

 Suata-pisco (Bird of the Year), because they make their appear- 

 ance together, in large flocks, about the end of the year (people 

 will tell you, precisely on Christmas-day), and remain througliout 

 January, when they are seen no more until the same epoch comes 

 round again. Mr. Bates has given a capital account of the move- 

 ments of these hunting-parties of frugivorous and insectivorous 

 birds, and of the superstition of the Papa-uird or Patriarch Bird, 

 who is supposed to head them (vol. ii. p. 333 e^ seq?). I suspect 

 that this is something more than mere superstition, and that the 

 Patriarch leaders are not one but several to each predatory band. 



The abundance of fish in rivers of white water, and their 

 scarcity in black-water rivers, may easily be shown to depend 

 chiefly on the luxuriant littoral vegetation of the former and its 

 scarcity or utter absence in the latter; for on the Eio Negro 

 there are (with one notable exception*) no aquatics, and no shore 

 grasses. Compare this with the broad fringe of tall succulent 

 amphibious grasses on the shores of the Amazon, or detached and 

 floating down it in the shape of large islands, — and of luxuriant 

 aquatics, some fixed by roots, others floating (Victoria, Jussicea, 

 Pontederia, Progbits, Azolla, Salvinia, Pistia, &c.), in deep still 

 bays, but especially in lakes and channels communicating with the 

 main river. 



Some of the tributaries of the Eio Negro, however, have plenty, 

 of fish — namely, those of more or less turbid water, of which the Eio 

 Brauco holds the first rank, and after it come the Marauia and 

 Cauaboris, all entering on the left bank. In these rivers many 

 Amazon fish are said to be repeated. About the mouth of the 

 Eio Branco is the only place in the Eio Negro where the Pirarucu is 

 found — that noble and remarkable fish, so characteristic of the 

 Amazon. With the exception of the Pirarucu, most of the larger 

 fish of the Amazon recur on the Upper Orinoco, above the cata- 

 racts ; at least the Indians assert them to be the same, and to un- 

 skilled eyes they are undistinguishable. The Valenton, or Lablab, 

 of the Orinoco (for instance) is surely the same as the large 

 Pirahyba of the Amazon ; the Pavon as the Tucunare ; the Eal- 



* That of the Podosteiuons on granite rocks in the falls and rapids. 



