The anisoptera (commonly known as dragonflies), are paleópteros, that is to say, insects that can not fold the wings on the abdomen. They are characterized by their large multifaceted eyes, their two pairs of strong transparent wings and their elongated abdomen (your photos are good and they manage to show these characteristics). They feed on mosquitoes and other small insects such as flies, bees, butterflies and moths.

Its natural habitat is in the vicinity of lakes, puddles, rivers and swamplands, since its nymphs are aquatic. Dragonflies do not bite humans and are valuable predators, since they control the populations of flies and mosquitoes, some of which transmit diseases such as dengue. (https://en.wikipedia.org/wiki/Anisoptera)
Never imagine that dragonflies could help control dengue disease. New knowledge
Greetings @jgullinese.