XXXVIi 
to belong to groups which are widely mimicked. Further- 
more, in all but H. dubia the non-mimetic males preserve the 
ancestral patterns of the females. 
In Heliconius microclea and H. xenoclea the difficulty is 
much greater. Their sexes are alike in pattern while they 
both belong to the distasteful, mimicked genus Heliconius. 
Assuming that they are equally distasteful, and that, on the 
Miillerian principle, it would be an advantage to them both 
to possess a similar warning pattern, then, other things being 
equal, the approach will be from the pattern of the less 
numerous to that of the more numerous. But other things 
may be unequal; one species may be constant and the other 
variable, and this difference may cause a more abundant 
Heliconius to mimic a less abundant one. Of the two species, 
xenoclea is the more variable and its pattern possesses the 
dyslegnic border which lends itself to variability and is com- 
monly characteristic of mimics as compared with their models. 
The description of both species as eulegnic in Proc. Linn. Soc. 
Lond., 1915-16, p. 52, was based on insufficient material, 
although here it was recognised that the inner marginal edge 
of the central fore-wing patch in wenoclea was less eulegnic 
than other parts of the border. Since the publication of this 
paper an interesting collection made in W. Central Peru by 
Mr. G. H. Bullock, of H.M. Consular Service at Lima, has 
thrown further light on the subject. The following series of 
the two Heliconines was taken by Mr. Bullock near the 
junction of the Chanchamayo River with the Perené River, 
at a height of about 3000 ft., the season being intermediate 
between wet and dry. 
Heliconius Heliconius 
Captured in 1918, notabilis xenoclea 
microclea. xenoclea 
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