Key to males of Epigomphus species in Costa Rica
1. Second pale antehumeral stripe reduced to a single small posterior spot.......................................... 2
1. Second pale antehumeral stripe consisting of a stripe and a posterior spot......................................... 7
2. Epiproct distinctly shorter than cercus.................................................................... 3
2. Epiproct as long as or longer than cercus................................................................... 5
3. Apex of epiproct with two sharp points............................................................. subsimilis
3. Apex of epiproct with one short tooth..................................................................... 4
4. Tooth at apex of epiproct pointing upward........................................................ tumefactus
4. Tooth at apex of epiproct pointing inward.......................................................... houghtoni
5. Apex of epiproct in lateral view truncate, with a small sharp tooth on upper angle; dorsum of S10 with a hump..... camelus
5. Apex of epiproct in lateral view not truncate; dorsum of S10 smoothly rounded................................... 6
6. Apex of cercus in lateral view emarginate with two acute tips........................................... quadracies
6. Apex of cercus in lateral view not emarginate...................................................... verticicornis
7. Second pale antehumeral stripe broken in the middle, separate from a posterior spot................................ 8
7. Second pale antehumeral stripe unbroken and connected to posterior spot......................................... 9
8. Epiproct much longer than cercus.................................................................. echeverrii
8. Epiproct about the same length as cercus........................................................ bosquenuboso
9. Epiproct about as long as cercus........................................................................ 10
9. Epiproct distinctly shorter than cercus.................................................................... 11
10. Apex of epiproct in lateral view with lower margin rounded and upper margin ending in an acute tooth; in ventral view branches forming a V-shaped sinus with an angle less than 80 degrees.................................. subobtusus
10. Apex of epiproct with lower margin square angled and upper margin with an acute recurved tooth; in ventral view branches forming a V-shaped sinus with a 95 degree angle..................................................... morrisoni
11. In ventral view branches of epiproct forming a V-shaped angle........................................... armatus
11. In ventral view branches of epiproct not forming a V-shaped angle............................................. 12
12. In ventral view branches of epiproct forming a broadly U-shaped sinus................................. corniculatus
12. In ventral view branches of epiproct short and barely forming a shallow sinus................................ wagneri