Sevan} 
HELICONINS. 
Heliconius vetustus—1. 
Eueides, vn. sp.—l. 
Thus a single species, J/. 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 LZ. pasinuntia. The single Z. ceves was an 
intermediate example. One specimen of Melinea crameri 
was broadly barred, and another faintly so. In Mr. Kaye’s 
experience this species had hitherto always been black. 
Mechanitis 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. Alechanitis 
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 
Melinea mneme 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 Zthomiine. They included 5 Scada theaphia, 
but no other member of its group; | Lthomia zarepha, but in 
this case also no other member of the group; 16 ceratinia 
vallonia, 1 Napeogenes pheranthes, another obvious member of 
