
1) Arachnid anatomy
Found on
https://www.crosswordclues.com/clue/epigyne

The epigyne or epigynum is the external genital structure of female spiders. As the epigyne varies greatly in form in different species, even in closely related ones, it often provides the most distinctive characteristic for recognizing species. It consists of a small, hardened portion of the exoskeleton located on the underside of the abdomen, in...
Found on
http://en.wikipedia.org/wiki/Epigyne

A more or less sclerotized and modified external structure associated with the reproductive openings of adult females of most spider species.
Found on
http://www.xs4all.nl/~ednieuw/Spiders/Spiderglossary.htm
No exact match found.