Zoology. — “The wing-design of mimetic butterflies’. By Prof. J. 
F. vaN BEMMELEN. 
(Communicated at the meeting of Nov. 27, 1920). 
In a paper: On the phylogenetic significance of the wing-markings 
of Rhopalocera, read before the meeting of the second International 
Entomological Congress at Oxford in 1912, | made the casual remark 
that “while inspecting the series of butterflies in search for speci- 
mens showing the primitive colour-pattern, | was greatly impressed 
by the considerable percentage of mimetic forms among my harvest. 
So the idea occurred to me that perhaps Mimetism might, at least 
to a certain degree and for a limited number of cases, be explained 
by supposing the resemblance between two or more non-related 
forms to have started at an early period, when the ancestral types 
of different butterfly-families looked more like each other than 
nowadays, on account of the primitive colour-pattern common to 
them all”. 
Since those days I have tried to clear and widen my ideas about 
the real character of the primitive colour-pattern, especially by a 
detailed analysis of the wing-design in original forms such as the 
Hepialids, and by its comparison to the pattern of the body. These 
investigations have led me to a modified conception of primitiveness 
in pattern: the occurrence of sets of uniform spots, regularly arran- 
ged in rows between the wing-veins, and spread over the entire 
wing-surface, appearing to me as a still more original condition 
than the concentration of the markings in the shape of a stripe 
along the middle-line of the internervural cells. But this does not 
in the least weaken my conviction, that this latter arrangement has 
retained a considerable amount of primitiveness also, and that its 
origin lies far beyond the beginnings of genera, families, nay of the 
whole order of Lepidoptera. 
Since then the Groningen Zoological Laboratory has acquired the 
magnificent collection of Lepidoptera left by the lamented Max 
FürBriNGER in Heidelberg. Thereby I was enabled to study actual 
specimens of mimetic butterflies in nature and this made me wish 
to return to the question of Mimetism in general, but then 
considered exclusively from a purely morphological standpoint. I desire 
therefore to avoid carefully the biological side of the question, 
though I may be allowed to express my conviction that the often 
