OF THE AMAZON VALLEY. 499 



Gallinacea {Toiclopidce and Cracida;), and other groups of tho same region, point to 

 the gradual adaptation of the fauna, during an immense lapse of time, to a forest-clad 

 country. 



I found on the hanks of the Amazons 9i species (l)csides many local varieties, con- 

 sidered hy some authors as species) of the two groups (07 Uanaoid and 27 Aera-oid), 

 representing all the genera of the iamily hut three. They are most numerous in those 

 parts of tiie country where the forests are most extensive and the climate most sultry and 

 humid. I found t he numher of species to increase in travelling from east to west, from the 

 Lower Amazons towards the eastern slopes of the Andes. They were rare in the scmiewhat 

 drier tract of country which horders the Lower Amazons ahout the middle of its course. 

 I found in this large district only 20 species, namely, 10 helonging to the Danaoid and 

 10 to the Acraioid group. "Within an area of ahout the same dimensions, in tlu^ moist 

 region of the Uijjx'r Amazons, I collected 1 species, of which i2 were Danaoid aiul 

 22 Acra^oid Ilellcnn'nlm. I should judge, from the collections received in England 

 from tliose parts, that the hot .Vndean valleys near Bogota, or in Ecuador, contain a 

 still larger nimiher of species tlian the plains of the Upper Amazons. In the dry forests 

 which clothe a great part of the hanks of the Tapajos I found exceedingly few : at oni' 

 locality, where I collected fom- months, and which was rich in other families of Lepi- 

 doptcra, I saw only one species of the Danaoid and four of the Acnuoid group. Accord- 

 ing to Dyson, many species {Illioniue) of the lowlands in Venc^zuela have a vertical range 

 of 2000 feet, and souk; genera {Ili/u/eiuiis [II. Dercelis], Olyras, Ei'trcsia), which do not 

 inhahit the Amazon region, occur at an elevation of 8000 feet. The species arc exceed- 

 ingly ahundant in individuals wherever they occur: they show every sign of flourishing 

 existence^ although of slow flight, feehle structure, unfurnished with ap[)arent means of 

 defence, and living in ])l;ices which are incessantly haunted hy swarms of insect ivcn-ous 

 hirds. The patliw.nys in the forest near towns are (piite enlivfMied hy the multitudes 

 wliieh fly al)out amongst the lower trees, in their hright dresses of orange, hlue, and 

 yellow, and red and l)laek. 



The mode of flight of the meml)ers of the two groups is somewhat (lilfercMit. The 

 Ilclicoiiii and Ei'ciilcs move along in a sailing manner, often circling round for a con- 

 siderahle time, with their wings horizontally extended. The species of tiie Danaoid 

 grcni]), for the most i)art, keep near the ground, and have a very slow irregular flight, 

 settling fnujuently. They are all of social or grcgax-ious hahits. ^sot only do individuals 

 of the same species congregate in masses, hut the set of closely allied sp(>cies which ])eople 

 a district keep together in one or more compact flocks. 1 noticed in four districts I'ich in 

 Danaoid IIrHconi<he, where I collected, that ahout half the speci(>s of Itlio)iiia Ih-w 

 together in one circumscribed area of the forest, and the other half in a second similar 

 locality, tlie rest of the toleral)ly uniform wooded country, in each case, heing nearl\ 

 untenanted hy them. The larger species {Ileliconii, Lijcorcw) frecjuent flowers, prol)ing 

 the nectaries with tiu'ir prol)oscides ; hut the smaller kinds {Itltomuc), and the memlier> 

 ol' the Danaoid group generally, are very rarely fouiul thus occupied: I noticed them 

 sometimes imhihing drops of moisture from leaves and twigs. The line showy Ilcliajiiu 

 often assemble in snuiU parties, or by twos ami threes, apparently to sport together or 



