Chap. V. 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 



