1/2 



THE LOWER AMAZONS 



fore give an account of one very instructive case which 

 presented itself in this neighbourhood. 



The case was furnished by certain kinds of handsome 

 butterflies belonging to the genus Heliconius ^, a group 

 peculiar to Tropical America, abounding in individuals 

 everywhere in the shades of its luxuriant forests, and pre- 

 senting clusters of varieties and closely allied species, as 

 well as many distinct, better marked forms. The closely 

 allied species and varieties are a great puzzle to classi- 

 fiers ; in fact, the group is one of those wherein great 

 changes seem to be now going on. A conspicuous mem- 

 ber of the group is the H. Melpomene of Linnssus. This 

 elegant form is found throughout Guiana, Venezuela, 

 and some parts of New Granada. It is very common at 

 Obydos, and reappears on the south side of the river in 

 the dry forests behind Santarem, at the mouth of the 

 Tapajos. In all other parts of the Amazons valley, east- 

 ward to Para and westward to Peru, it is entirely absent. 

 This absence at first appeared to me very strange ; for 

 the local conditions of these regions did not appear so 

 strongly contrasted as to check, in this abrupt manner, 

 the range of so prolific a species ; especially as at Obydos 

 and Santarem it occurred in moist woods close to the 

 edge of the river. Another and nearly allied species, 

 however, takes its place in the forest plains ; namely, 

 the H. Thelxiope of Hiibner. It is of the same size and 

 shape as its sister kind, but differs very strikingly in 

 colours : H. Melpomene being simply black with a large 

 crimson spot on its wings, whilst H. Thelxiope has these 

 beautifully rayed with black and crimson, and is further 

 adorned with a number of bright yellow spots. Both 

 have the same habits. H. Melpomene ornaments the 

 sandy alleys in the forests of Obydos, floating lazily in 

 great numbers over the lower trees ; whilst H. Thelxiope, 

 in a similar manner and in equal numbers, adorns the 

 moister forests which constitute its domain. No one 



^ This genus has long been known under the name of 

 Heliconia : a most inconvenient term, as a botanical genus 

 bears the same name. An author has lately proposed to revert 

 to the masculine termination of the words as first employed 

 by Linnaeus (Felder, in the Wiejier Entomologische Monat. 

 schrift^ March, 1862), and, as I think the correction a good 

 one, I adopt it. 



