Chap. Y. 
BUTTERFLIES. 
347 
absent or very sparingly represented on the Lower 
Amazons within reach of the trade winds. The range 
of these nineteen genera is affected by a curiously com- 
plicated set of circumstances. In all the species of 
which they are composed, the males are more than 
100 to one more numerous than the females, and being 
very richly coloured, whilst the females are of dull hues, 
they spend their lives in sporting about in the sun- 
light, imbibing the moisture which constitutes their 
food, from the mud on the shores of streams, their 
spouses remaining hid in the shades of the forest. The 
very existence of these species depends on the facilities 
which their males have for indulgence in the pleasures of 
this sunshiny life. The greatest obstacle to this is the 
prevalence of strong winds, which not only dries rapidly 
all moisture in open places, but prevents the richly- 
attired dandies from flying daily to their feeding-places. 
I noticed this particularly whilst residing at Santarem, 
where the moist margins of water, localities which on 
the Upper Amazons swarm with these insects, were 
nearly destitute of them ; and at Villa Nova (where a 
small number exists) I have watched them buffeting 
with the strong winds at the commencement of the dry 
season, and, as the dryness increased, disappearing from 
the locality. On ascending the Tapajos to the calm and 
sultry banks of the Cupari, a great number of these 
insects re-appeared, most of them being the same as 
those found on the Upper Amazons, thus showing clearly 
that their existence in the district depended on the 
absence of winds. 
Before proceeding to describe the ants, a few remarks 
