The Cerulean Dancer Damselfly (Argia anceps), male here, is one of dozens of blue and black damselflies with this one most often confused with the Azure Dancer and the Thorn-tipped Dancer (says the book), but because of the shade of blue, the size and the wing color I am declaring this a Cerulean Dancer! :-) But to be honest, with both damsel and dragonflies, I am seldom 100% certain of the identification and I use a Costa Rica specific field guide with nearly 300 species of damselflies and dragonflies included with photos! You would think that makes it easy, but not for me! The many similarities between species makes identification a challenge for many! This one was photographed on the railing of my terrace in Atenas, Alajuela Province, Costa Rica.
See my Dragonflies & Damselflies GALLERY with 50+ species! And many are unidentified! :-)
¡Pura Vida!