Table 1. Average pairwise sequence divergence between alleles within the two colour pattern-determining regions (%).

DENNIS	Outgroup	Silvaniforms	Dennis	Postman
Outgroup	14.5	17.6	17.5	16.9
Silvaniforms		3.8	4.1	5.3
Dennis			1.5	5.3
Postman				1.6
RAY	Outgroup	Silvaniforms	Ray	Postman
Outgroup	13.6	16.7	17.5	17.5
Silvaniforms		3.6	7.0	7.3
Ray			1.1	2.7
Postman				1.2
FLANK—D	Outgroup	Silvaniforms	Dennis	Postman
Outgroup	16.0	16.5	17.0	16.8
Silvaniforms		3.2	3.8	3.6
Dennis			2.4	2.3
Postman				1.1

Individuals were grouped by their phenotype rather than taxonomy, and average percentage pairwise divergence was calculated within either the dennis (top) or ray (middle) region alignments. All silvaniforms are grouped together except for H. elevatus, which is grouped with the dennis/ray melpomene and timareta morphs. As a control, a flanking region distal to the dennis allele relative to optix (see Fig 3) is also shown (bottom). The dennis and postman alleles are equally different to the silvaniforms for sequences outside the putative dennis region, as would be expected from the species tree. See S2 Table for divergences of ray individuals at the dennis region and dennis individuals at the ray region.