INSESSORES. 305 



two feet high, which was entered by Humboldt and his com 

 panions. After penetrating not far from four hundred and fifty 

 feet, they heard from afar the hoarse cries of the Guacharo 

 Birds. These birds quit the cavern only at nightfall, especially 

 when there is moonlight. Elumboldt remarks that they are the 

 only friagivorous birds of the night yet known. They feed on 

 very hard fruits, and reject the insect food of which other Goat- 

 Suckers are fond. Once a year, near midsummer, this cave is 

 entered by the Indians. Armed with poles, they ransack the 

 greater part of the nests, while the old birds hover over the heads 

 of the robbers, as if to defend their brood, uttering, at the same 

 time, horrible cries. The young which fall down are killed 

 upon the spot. The inner parts of these birds are laden with 

 fat ; darkness and repose, as Humboldt suggests, favoring its for 

 mation, as in the case of geese and oxen. The fat of these birds, 

 when melted, is called the butter or oil of the Guacharo ; it is 

 half liquid, transparent and inodorous, and so pure that it will 

 keep a year or more without becoming rancid. The crops and 

 gizzards of the young birds, when opened in the cavern, are 

 found to contain all sorts of hard and dry fruits, which are con 

 veyed to them by their parents. These are preserved, and, un 

 der the name of Guacharo-seed, are considered a remedy against 

 intermittent fevers. The cave of the Guacharo is situated in 

 South Lat. 10o 10 . 



SECOND FAMILY. The SWALLOWS or MARTINS. 

 Hirundinidce, (Lat. Hirundo, a swallow.) 



The family of Swallows resemble the Night-jars in the small- 

 ness of the beak, and the great width of the gape, as they do also 

 in the weakness and greatly reduced size of the feet. They, 

 however, differ from the Night-jars in being active during the 

 day, and hence are included in the sub-tribe, Fissirostres diurni, 

 or Diurnal Split-billed Birds. The Swallows are also of far 

 more powerful wing than the Night-jars, nor have their feathers 

 the lax softness, or the mottled style of coloration common to 

 birds of the night ; but on the other hand, the plumage is close, 

 smooth, and often burnished with a metallic gloss; while the pre 

 vailing shades are black, (more or less changing into blue or 

 green.) above, and white, often varying with dull red, beneath. 



The smallness of their feet is in correspondence with their al 

 most perpetual flight ; they even drink on the wing ; and their 

 feet, being small and weak, are little used, yet as these birds 

 often cling to rocks and walls when they do rest, their toes are 



