Chap. VI. ORIGIN OF SPECIES. 257 



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 Hubner. 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 



Heliconius Thelxiope. 



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 



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