112 : THE ENTOMOLOGIST. 
This interesting form is the only representative of M. sociata 
in the Isle of Lewis, and occurs there in June and August. 
MELANIPPE RIVATA. 
Sylvaticata, Haworth, Wood. 
Generally larger than M. sociata, but similar in colour and 
pattern. On the fore wing the central fascia is usually broader, 
deeper in colour, and the intersecting black-bordered pale line is 
nearer the outer edge ; the white bands are, as a rule, broader, 
and the intersecting grey line of the outermost is only distinct 
towards costa; the outer marginal area of the wing is paler 
grey, and is sometimes tinged with bluish, in the upper portion 
there is an oblique pale irregular dash from the apex to sub- 
marginal line, and below this there are two blackish longitudinal 
bars intersected by the white submarginal line, and edged with 
rusty brown on the outer margin. Hind wing white, with a 
large black discoidal spot; the base is greyish up to the first of 
three narrow transverse central grey bands, which do not always 
reach the costa; the outer marginal area is of the same colour 
as that of fore wing, but the intersecting line is rather broader ; 
there is sometimes an indistinct greyish line between this area 
and the third transverse grey band. Fringes as in M. sociata, 
but the black line is more distinctly evident. Thorax pale grey, 
with several black dots. 
Entomologists do not appear to be agreed as to the distinct- 
ness of this species from M. sociata. Forms of the latter cer- 
tainly come very close to rivata, but they always lack one or 
more of the characters of that insect. 
I can hardly point out any particular feature that will serve 
to distinguish the one species from the other. Absence of 
brownish tinge on the outer marginal area will not alone suffice, 
as some undoubted specimens of sociata have this portion of the 
wings coloured exactly as in rivata. The width of the central 
grey fascia is not worth much by itself, as some examples of 
sociata have a broader fascia than some specimens of rivata. 
The white bands, too, are often as broad in certain examples of 
sociata a8 in any specimen of rivata. On the under surface of 
the fore wings of rivata the submarginal white line is broken up 
into dots towards the costa, but we shall find that this is also 
the case in some examples of sociata. 
The paler thorax, with distinct black dots in conjunction with 
broad white bands on all the wings, and the abbreviated character 
of the central lines on hind wings, are of service in the identi- 
fication of rivata. 
I have taken sociata at various times and places from May to 
August, but I have only met with rivata on the wing in June. 
Second broods of the last-named have been bred in confinement, 
