36 Bangs — Rare or Not Well Knoivn Costa Rican Birds. 



Vireolanius pulchellus viridiceps Ridg. 



At El General (Pacific fauna) on June 20, 1908, Underwood took an 

 adult male and female of this well-marked form. 



Vireolanius pulchellus verticalis Ridg. 



Two specimens, adult male and female, were secured by Underwood at 

 La Vijagua (Carib])oan fauna) on February 24 and 25, 1908. These two 

 races are beautifully distinct, and as the shrike-vireo is one of tlie really 

 very rare Costa Rican birds, the records of additional localities are worth 

 making. 



Hirundo erythrogastra Bodd. 



In the latter part of May, 1908, l)arn swallows were abundant at Buenos 

 Aires, and Underwood took a small series of specimens between the 2.'')d 

 and 26th. The birds were apparently not breeding, but were belated 

 migrants. The late dates at M'hich many other North American species 

 still linger in Costa Rica was a revelation to me as I began to receive col- 

 lections from that country, and I am still at a loss to account for it. 



Wilsonia pusilla pusilla (Wils.). 



Three specimens, all referable to this sub-species, were taken — one 

 female on Tonorio February 1, 1908, two males in the Cerro Sta. INIaria 

 January 4 and 8, 1908 — by Underwood last winter. Tlie identification is 

 positive; I myself felt sure of it, but to be doubly certain sulnnitted the 

 skins to Ridgway, who confirmed my ojMniou. The bird in winter plu- 

 mage can be told from W. pusilla pileolata not only by its duller colora- 

 tion, but by its smaller size, especially shorter wing. This record extends 

 the southward range of the form in winter by a consideral)le distance, 

 southern Mexico being, I believe, the farthest south it had previously been 

 taken on the continent. W. pusilla pileolata (Pallas) is very abundant 

 in winter, especially at higher elevations in southern and central Costa 

 Rica and Chiriqui, and remains till late in May. It was not, however, 

 found l)y Underwood in northern Costa Rica during his last year's work. 



Basileuterus rufifrons mesochrysus (Scl.). 



A large series taken at Buenos Aires and El General, both places within 

 the south-Pacific faunal area of Costa Rica, in May, June and July, rep- 

 resents this form apparently in its extreme, the specimens being quite indis- 

 tinguishable from examples from Colombia and Panama. I also iind 

 that skins from the Boruca region of Costa Rica, formerly referred to 

 B. rufifrons delattrii (Bonap.) by me,* belong here. 



Basileuterus rufifrons delattrii (Bonap.) was also taken in large series 

 on Tenorio and in the Cerro Sta. Maria, and this form ajtpears to occupy 

 all eastern and northern C'osta Rica, from the vicinity of Sun Jose north- 

 ward and eastward. 



The two sub-species are easily distinguished by well-marked dillereiu-es 

 in color, and by the much longer tail of B. rufifrons delattrii. At the 

 time I published the paper referred to I had no skins of this latter form. 

 * Auk, Vol. XXIV, p., :!0(i, July, 1907. 



