322 Annals of the Carnegie Museum. 



most wholly to the northwestern portion of the country, including the 

 Nicoya peninsula and the eastern mainland slope of the Gulf, but does 

 not extend south of the Rio Grande de Tarcoles Valley, with very few 

 exceptions. It is further characterized by a six months' dry season, 

 and by the presence of large areas of savanna, which are confined to 

 the region northwest of the Gulf of Nicoya. 



The most characteristic forms are : Catharus griseiceps (south of 

 Rio Grande), Planesticus tristis cnephosa, Heleodytes capistratits capi- 

 stratus, Salpinctes guttatus, Oryzoborusfunereus, Amaurospiza coucolor, 

 Colin iiiculus savannarum obscurus, Aimophila ruficanda ruficauda, A. 

 hotter ii sartorii, A. rufescens hypcetlirits, Agelaius phceniceus subsp.? 

 Icterus s c later i, I. pectoralis espinachi, Calocitta formosa azurea, Myio- 

 dynastes maculatiis nobilis, Myiarchus (several species) ; all of which 

 are confined to the Pacific. On the Caribbean are found : Catharus 

 mexicanus fumosus, Heleodytes zonatus costaricensis, Planesticus obso- 

 letus, Icterus mesomelas salvini, and /. pi'ostliemelas. 



Tropical. 



All of the forms under this head, whether in the humid, semi -arid, 

 or arid regions are supposed to be true Tropical forms or to be slightly 

 aberrant types of the Tropical fauna, which have spread northward 

 from the equatorial regions. 



Tropic Zone (o to 1,500 feet). 



This zone is confined to the Caribbean slope, embracing the whole of 

 the lowlands and lower foot-hills, and is characterized by a very heavy, 

 nearly continuous rainfall, luxuriant tropical jungles, composed of 

 plants and trees belonging entirely to the tropical flora. Practically all 

 the birds found here are species inhabiting woodland. Some are found 

 in the Pacific lowlands, others are represented there by slightly dif- 

 ferent races, while many are peculiar to this belt. Some of the most 

 characteristic species are : Leucolepis lawrencii, Henicorhina prost/ic- 

 leuca prostlieleuca, Thryophilus zeledo/ii, T. thoracicus, T. castaneus 

 costaricensis, Pheugopedius atrogularis, Vireolaniiis pulchellus 7'erticalis, 

 Eiiphonia gouldi, Ta?igara florida, T. lavinia lavinia, T. larvata lar- 

 vata, Buthraupis cozruleigularis, Phcenicothraupis fuscicauda, Lanio 

 leucothorax ', Mitrospingus cassiui, Tachyp/ionus delattrii, Pity/us gross us, 

 Caryothraustes poliogaster scapularis, Cyanocorax affinis zeledoiu, 

 Copurus leuco/iotus, Todirostrinn nigriceps, Perissotriccus atricapillus, 



