34 Bangs — Rare or Not Well Knmvn Costa Rican Birds. 



Myiarchus nuttingi nuttingi Ridg. 

 Myiarchus brachyurus Ridg. 



In Birds of North and Middle America, Ridgway expressed a doubt as 

 to the distinctness of these two tyrant birds, and gave brachi/rtrus snh- 

 specitic rank. I find, liowever, tliat my tliirty specimens from nortliern 

 and western Costa Rica fall without an intergrade, when compared by 

 measurements, into two series, one a large bird with a heavy bill (bra- 

 chyuriis); the other a small bird with a small, slender bill (nutthigi). 

 Correlated with this marked difference in size is a slight tlidugh constant 

 difference in color, which in skins taken in December, January and Fel)- 

 ruary is quite appreciable. In faded specimens I fancy it would not be so 

 easily detected; the smaller bird (nuttingi) being brighter yellow below, 

 and 1)rowner, less grayish olive above. 



As the range of these two tyrants is coincident over a very large area, 

 they can not be geographical races of one species, and as they certainly 

 seem distinct I believe Nelson's arrangement in his revision of the North 

 American Mainland Species of Myiarchus* the correct one. Plere Nelson 

 considered Myiarchus brachyurus specifically distinct from M. niiftliu/i 

 and 3/". mquirtus, a northern subspecies of nuttingi. 



Henicorhina prostheleuca (S'cl.). 



The case of the white-breasted wood wrens is another instance of a 

 large amount of material (my series now numbers two hundred skins) 

 proving that two races iiistead of one should be credited to C-osta Rica. 



Specimens from Carrillo, La Vijagua, Tenorio an<l Cerro Sta. Maria 

 are all referable to //. prostheleuca prostheleuca, Scl., some of them some- 

 what intermediate, but very many absolutely indistinguishable from 

 Mexican examples. Skins from any point in southwestern Costa Rica 

 belong, of course, to H. prostheleuca pillieri (Cherrie). The two sub- 

 species are easily told apart, one of the best charactt-rs being the color of 

 the median crown-stripe. 



Microcerculus. 



On his last collecting trip Underwood took examples of the nightingale 

 wren in Costa Rica as follows: 



El General (Pacific fauna), four fully adult males, June and Jiily, 

 La Vijagua (Caribbean fauna), one young male, one nearly fidly ailult 

 female, February; Cerro Sta. Maria (mostly but not wholly Pacific faiuia), 

 two males and one female, all immature, Jamiary; Tenorio (mostly but 

 not wholly Pacific fauna), two young females, February. 



These with three skins from Bociuete, on the VolcAn de Ciiirfqui, col- 

 lected by Brown (upon which I founded my M. acentetus) , gives me a 

 series of fourteen skins from Costa Rica and Chirfqui, that perplexes me 

 much, and causes me to doubt the existence in Central America of but 

 one form. For the help of any other ornithologist wIk^ uiay ))0 fortunate 

 enongii to secure a Ijetter series still of this t'lusive little ventrilocpious 

 inhabitant of tiie deej) forest I shall discuss the specimens pretty fully. 



• Proc. Biol. Soc. Wash., xvii, pp. 21-50, March 10, 1904. 



