2 males (images 1-5 with genitalia) and 1 female (6-7)
Labels:
Balzapamba / [Ecuador] / R. Haensch S.
donum Ch. Dupuis, Bruxelles, 1913
"Cyclocephala atricapilla Mannh."
Nonetheless, this species is not present in the check-list of Ecuadorian Dynastinae (http://museum.unl.edu/research/entomology/Ecuador-Survey/species.html)
Thank you in advance for your attention.
P.S. Might it be C. castanea?