XXXVl1 
Rehibitions. 
THE MIMETIC RELATIONSHIP BETWEEN HELICONIUS NOTA- 
BILIS MICROCLEA KAYE, AND H. XENOCLEA XENOCLEA Hew. 
—Prof. Poutron said that the interesting fact that species 
or subspecies of Heliconius belonging to Section I, the Opiso- 
gymni, mimicked species of the same genus in the same 
localities belonging to Section II, the Opisorhypari, had 
been demonstrated to the Society by Mr. W. J. Kaye (Proc. 
Ent. Soc. Lond., 1907, p. xiv) and more recently worked out 
in detail in Dr. H. Eltringham’s monograph (Trans. Ent. 
Soc. Lond., 1916, p. 101); and it had furthermore been 
shown that species of Opisogymni, which do not mimic the 
Opisorhypari, closely resemble Ithomine models, To this 
rule that the Opisogymni behave as mimics an exception was 
believed to be found in zenoclea, the supposed model for 
microclea (Opisorhypari). This view of the relationship was 
accepted by Mr. Kaye and Dr. Eltringham * in the papers 
quoted above, and it was based on the relative numbers of 
the two species to be found in collections. But relative 
numbers, although usually a trustworthy guide, did not always 
settle this question. The relative abundance of a species 
was determined by a variety of causes outside those which 
are believed to promote the evolution of mimetic resemblance 
—viz. the discriminating attacks of vertebrate enemies, 
especially birds. A mimic may be less attacked and less 
parasitised by invertebrate enemies than its model, may be 
more fertile, may have a more dominant food-plant. From 
causes such as these the predominance of certain mimics 
might probably be explained—of Hypolimnas misippus, bolina, 
and dubia, and of Papilio polytes—all very common species, 
known at certain times and places to outnumber their models. 
In all these examples, however, there is no difficulty in deciding 
that they are mimics and not models because, even if they 
are to some extent specially protected by taste or smell, the 
species they resemble are known to be highly distasteful and 
* On pages 112 and 117 Dr. Eltringham speaks of microclea as re- 
sembling wenoclea, but in his Plate XII, microclea (fig. 3) is represented, 
correctly in my opinion, as the model of xenoclea (fig. 4). 
