A bit of a search-and-find, but a good impression of a Microvelia colony. I photographed these Microvelia specimen in the Marimurtra botanical garden near Blanes, North of Barcelona (with a digital compact camera, therefore somewhat less detail). There are many nymphs. Bottom left: a winged adult specimen. Two wingless adult specimens are mating, middle top. Top right the skin of the pupa of a mosquito larva.

First picture: imago with silvery hairs on the thorax shield, second picture: a somewhat older nymph and below right a very young one. Judging by the overlaying pronotum (thorax shield) these tiny bugs could be Microvelia pygmaea. That species is common in Spain, and seems to be migrating more to North-Europe. This applies to more southern insects and is often seen as evidence of atmospheric warming.