Identification, Images, & Information
For Insects, Spiders & Their Kin
For the United States & Canada
A technical paper on genome sequencing, probably available only to those at academic institutions; but it discusses the C. cecrops and C. isobeon contrast in depth with reference to another couple of outgroup species from Central America. Supplemental Figure 3 has a variety of wing pictures of the four species.
https://www.ncbi.nlm.nih.gov/pubmed/28179510