Members of this family are commonly called broad-winged damselflies or jewelwings. In my opinion, these look like species which one would encounter in tropical climes rather than central Illinois. Yet, here they are.

Calopteryx maculata (dorsal view of adult)

Calopteryx maculata (Beauvois, 1807) [Ebony jewelwing] (Peoria Co.) Note: This species shows some sexual dimorphism. Females have a white spot near the tips of the wings; males lack these spots. 

Hetaerine americana (dorsal view of adult)

Hetaerina americana (Fabricius, 1798) [American rubyspot] (Peoria Co.)