DESCRIPTIONS OP NEW SPECIES AND GENERA OP BIRDS FROM 

 THE LOWER AMAZON. 



By ROBEQST RIDOU AY. 



The following novelties form part of a collection of birds made by 

 Mr. (J. B. Riker, of New York City, at aud near the settlement or 

 plantation of Diamantina,* near the town of Santarem, during the 

 months of June aud July, 1887. The total number of species collected 

 does not much exceed one hundred, but the proportion of novelties is 

 unusually large, a circumstance resulting from the excellent judgment 

 of the collector, who left the " beaten tracks " and turned his atten- 

 tion specially to the more inconspicuous species. In addition to the 

 new forms obtained, a considerable number were secured which have 

 been previously taken (so far as published records show) only on the 

 Upper Amazon or in Guiana. 



Specimens ol most of the new species have been presented by Mr. 

 Riker to the National Museum, among them several types. Three ad- 

 ditional new speciest are described separately, in special monographs. 



1. Thryothorus herberti Eikek, MS. 



Sp. char. — Similar to T. oyapocensis,\ but larger, the bill much larger 



* Mr. Eiker informs niB that Diamantina lies 2 miles back from an arm or chan- 

 nel of the Amazon, the Igarapc Mahicii, which is bordered by a dense swamp of palm 

 trees, almost impassable during the rainy season. Lying between this swamp and 

 the plantation is a semi-palm and second-growth forest, while 2 miles in the op- 

 posite direction is a sandy campos covered with clumps of bushes aud scrubby trees. 

 Half a mile east rises abruptly the commencement of a table-land, 300 feet high, 

 which slopes gradually to the cast for more than :>0 miles, and covered Avith dense 

 forest. 



A great difference in the fauuas of these several tracts was oI)served by Mr. Riker, 

 particularly among the insects, several of which Avere abundant on the table-laud 

 but never seen below. 



t Two species of Dcndroc'uicla and one of rnUtacula. 



! Thryothorus oyapocensis, sji. nov. 



Sr. CHAR. — Similar to T. coraya (Gm.), but lower parts, posterior to the throat, 

 pale, dull, grayish brown medially, the sides of the breast deeper brownish grayish, 

 passing into raw-umber brown on Hanks and thighs ; black bands on tail rather nar- 

 rower and black on side of head more restricted 



Adult (type, No. 90448, Oyapoc, French Guiana ; received from Messrs. Salvin and 

 Godman) : Pileum aud hind-neck deep brown (between Proufs brown aud bistro) ; 

 rest of upper parts (except tail) uniform deep chestnut, the upper tail-coverts lighter 

 aud duller, and very indistinctly barred with darker. Tail banded or broadly barred 

 Avith black and pale grayish brown, the bauds of the former about ten in number, and 

 averaging about .10 in Avidth. A distinct though narrow superciliary stripe of AAhite ; 

 lores, auriculars, and malar region black, the auricular^ linely streaked Avith Avliite. 

 Chin aud throat dull white, passing into A'cry pale grayish broAvn (almost soiled 

 white) on median portion of breast and belly, and into dull brownish gray on sides of 

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