74 MR. H. W. BATES ON THE INSECT FAUNA 
moved than one hundred to two hundred miles. Such species, how- 
ever, have often the character of local varieties, some of them 
indeed showing the connecting links. From facts observed, it 
would seem that the excessive multiplication together with the 
distinctness of the species were owing to their great susceptibility 
of modification, combined with the habit in pairing of selecting 
none but their exact counterparts, and probably other causes tend- 
ing to eliminate the intermediate gradations. The species are 
mostly extremely numerous in individuals, and show every sign 
of flourishing existence, although they are of feeble structure, and 
fly slowly in exposed situations frequented by swarms of insec- 
tivorous animals. They are gregarious in habits, the individuals 
of the same species and clusters of closely allied species bemg 
found in company restricted to limited spots in the forest. They 
are often seen in pairs or small parties, apparently engaged in a 
kind of dance. The large handsome species are so numerous in 
some places that they form part of the physiognomy of the localities. 
The only secondary sexual characters are tufts of hairs on the fore 
margin of the hind wing in the males of most of the Acreoid 
group. These appear to be of no particular utility, but are 
apparently analogous to the pencil of hairs on the breast of the 
male turkey. The allied group, Danaine, afford a similar fea- 
ture, the males having a horny excrescence on the disk of the hind 
wing, which is evidently homologous with the structure above de- 
scribed. The most interesting part of the natural history of the 
_  Heliconine is the mimetic analogies of which they seem to be the 
“objects. This involves questions of the highest scientific interest. 
Many of the species are mimicked by members of widely distant 
groups, ¢.g. Papilio and Leptalis (Papilionide), Ithomeis (Hry- 
cinide), Castnia (Castniade), Dioptis, Pericopis, Hyelosia, &c. 
(Bombycide moths). It is fair to conclude that they are the 
objects imitated, because they all have the same family facies, 
whilst the analogous species are dissimilar to their nearest allies 
—perverted, as it were, from the normal facies of their genera or 
families. The mimicking species are found in company with the 
Heliconine ; and it often happens, where these latter are modified 
into local varieties, species or local varieties of the former in an 
analogous dress also occur with them. A parallel series of imita 
tions occurs in the old-world tropics, where it is the represen-| 
tatives of the Heliconine that are the objects imitated. The 
instance of this kind of analogy most familiar to European ento- 
mologists is that of the species of Zvochilium (a genus of moths), 
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