OF THE AMAZON VALLEY. 499 



Gallinacea {Penelopidce and Cracidce), and other groups of the 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 banks of the Amazons 94 species (besides many local varieties, con- 

 sidered by some authors as species) of the two groups (67 Danaoid and 27 Acrasoid), 

 representing all the genera of the family but three. They are most numerous in those 

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

 humid. I found the number 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 somewhat 

 drier tract of country which borders the Lower Amazons about the middle of its course. 

 I found in this large district only 26 species, namely, 10 belonging to the Danaoid and 

 16 to the Acrseoid group. Within an area of about the same dimensions, in the moist 

 region of the Upper Amazons, I collected 64 species, of which 42 were Danaoid and 

 22 Acrseoid ILeliconidce. I should judge, from the collections received in England 

 from those parts, that the hot Andean valleys near Bogota, or in Ecuador, contain a 

 still larger number of species than the plains of the U|)per Amazons. In the dry forests 

 which clothe a great part of the banks of the Tapajos I found exceedingly few : at one 

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

 doptera, I saw only one species of the Danaoid and four of the Acrseoid group. Accord- 

 ing to Dyson, many species [Ithomiae) of the lowlands in Venezuela have a vertical range 

 of 2000 feet, and some genera {SymeniUs [^S. Bercetis], Olyras, Etttresis), which do not 

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

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

 existence, although of slow flight, feeble structure, unfurnished with apparent means of 

 defence, and living in places which are incessantly haunted by swarms of insectivorous 

 birds. The pathways in the forest near towns are quite enlivened by the multitudes 

 which fly about amongst the lower trees, in their bright dresses of orange, blue, and 

 yellow, and red and black. 



The mode of flight of the members of the two groups is somewhat different. The 

 Meliconii and Eueides move along in a sailing manner, often cu'cling round for a con- 

 siderable time, with their wings horizontally extended. The species of the Danaoid 

 group, for the most part, keep near the ground, and have a very slow irregular flight, 

 settling frequently. They are all of social or gregarioiis habits. Not only do individuals 

 of the same species congregate in masses, but the set of closely allied species which people 

 a district keep together in one or more compact flocks. I noticed in four districts rich in 

 Danaoid HeUconidce, where I collected, that about half the species of Ithomia flew 

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

 locality, the rest of the tolerably uniform wooded country, in each case, being nearly 

 untenanted by them. The larger species {Seliconii, Lycorece) frequent flowers, probing 

 the nectaries with their proboscides ; but the smaller kinds {Ithomice) , and the members 

 of the Danaoid group generally, are very rarely found thtis occupied : I noticed them 

 sometimes imbibing drops of moisture from leaves and twigs. The fine showy Helicotiii 

 often assemble in small parties, or by twos and threes, apparently to sport together or 



