500 MR. H. W. BATES ON THE LEPIDOPTERA 
perform a kind of dance. I believe the parties are composed chiefly of males. The 
sport begins generally between a single pair: they advance, retire, glide right and 
left in face of each other, wheel round to a considerable distance, again approach, and 
so on : a third joins in, then a fonrth, or more. They never tonch : when too many 
are congregated, a general flutter takes place, and they all fly off, to fall in again by pairs 
shortly afterwards. The species which I have seen most frequently employed in this 
way is the Heliconius Mhea, a glossy blue-black species, with bright yellow belts across 
its wings. 
The larvae of the two or three species whose transformations I observed feed together 
in clusters on the leaves of trees of moderate elevation, near the places where the adult 
insects are found. 
The majority of the species have very limited ranges. I was surprised, when travelling 
on the Upper Amazons from east to west, to find the greater part of the species of 
IthomicB changed from one locality to another, not further removed than 100 to 200 
miles. For instance, there were 11 of these Itliomice at a place called Fonte Boa, and 
9 at St. Paulo, 180 miles distant ; but only two of the total number (20) were found in 
both localities. This is remarkable when we consider that the whole of the country of 
the Upper Amazons is a nearly level plain, uniformly covered with forest, and offering no 
perceptible difference in soil or other physical conditions. Five only out of the 20 species 
have been met with in any other part of South America. The areas of distribution of 
most of the remaining 15 must be, in each case, a very limited tract of country. The 
species which inhabit other parts of Tropical America must have similarly contracted 
ranges, if we may judge from the collections received in England from different districts. 
Now, many of these local species have the appearance of being geographical varieties ; 
I could not help suspecting them to be such when I met with them in nature, the dif- 
ferences between the forms of one and those of another locality relating in many cases 
simply to the colours and colour-patterns of the wings. The marks of distinction, how- 
ever, are in the majority so well defined, so ordinarily common to all the individuals 
concerned, and there is so generally an absence of connecting links, that they are held 
on all hands to be good and true species. Moreover, in those cases already mentioned, 
where a number of very closely allied species fly together, they keep themselves per- 
fectly distinct ; there are no hybrid forms (I am speaking of the Ithomice and allied 
genera) , and on observing individuals in copula, I almost always * found the pair to be 
precisely the same in colours and markings. In the multiplicity, apparent distinctness, 
and restricted ranges of the species, this group much resembles the family of Humming- 
birds of the same regions. 
I believe, nevertheless, that the suspicion of many of the species being nothing more 
than local modifications of other forms has proved to be well founded. Amongst 
the great number of perfectly distinct and well-marked species, a few occurred which 
showed great variability : these, I think, afford a key to the explanation of the origin 
of the rest. The details of variation will be given under the head of each species : 
* The exception was in the case of Mechanitis Polvmnia. which, as will he seen, on referring to the account of it 
an 
