( Iv ) 

 DaXA1N-E. 



Lycorea ceres — 1. 



,, i^asinuntia — 3. 



HeliconiX-F,. 

 Heliconius vetustiis — 1. 

 Utieides, n. sp. — 1. 



Thus a single species, JI. mneme, entirely dominates the 

 group. Beautiful series exhibiting transition from the barred 

 to the black-hind-wing were seen in this species, and in the 

 3 individuals of L. pisiniintia. The single L. ceres was an 

 intermediate example. One specimen of Melinsea crameri 

 was broadly barred, and another faintly so. In ^Ir. Kaye's 

 experience this species had hitherto always been black. 

 Jfechciiiifis n. sp. included a fine transitional series, but, as 

 in other examples from this district, the black mark- 

 ings were very heavy even in the lightest forms. Mechanitis 

 polymnia was, as usual, an antithesis to the last-named, the 

 blackest hind wings being still distinctly barred. 



Comparing these and other specimens in the Hope Depart- 

 ment, and Mr. Kaye's fine series, with Oxford specimens of 

 the same or representative species from Surinam, it appears 

 certain that the Potaro district must stand on the fringe of 

 the area where this black-hind-winged group is developing. The 

 ancestral barred pattern and the various grades of intermediates 

 which occur so abundantly with the black on the Potaro road 

 are apparently far less common in Surinam, and are probably 

 less common still in French Guiana. We do not, however, 

 know the distance to which the group extends along the coast 

 or into the interior. The apparent anomaly of the dominant 

 Melinsea vinerae exhibiting the most ancestral series of any 

 species in the group may be merely a result of this position on 

 the fringe of the area. Extended observations are greatly 

 needed ; for, so far as it is possible to judge from the facts 

 before us, more could be learnt of the origin and more inferred 

 as to the bionomic significance of this black-hind-winged 

 group of the Guianas than any other in the world. 



The remaining specimens, with the exception of a single 

 Hesperiid, were all Ithomiinse. They included 5 Scada theaphia, 



