Omaliinae can be recognized easily by the presence of a pair of ocelli behind the compound eyes (Fig. 1.15.1). However, individuals of Pycnoglypta Thomson and Eusphalerum Kraatz sometimes lack ocelli. Eusphalerum species in ECAS are always yellowish-brown with a habitus as in Fig. 1.15.2. The two Pycnoglypta species in ECAS are similar in habitus to Fig. 1.15.3.

Omaliines are widely distributed in North America and can be collected year-round although the greatest diversity occurs in fall to early spring. They can be collected by sifting litter in forests and along wet areas (Fig. 9.7.1), in fungi, on flowers, in sweeps and pan traps placed in grassy areas, under stones near water (Fig. 9.7.2), and on the snow surface in late winter (Fig. 9.7.3). Some species aggregate on surfaces in fall and can be relatively conspicuous (Fig. 9.7.4). Many Omaliinae are predators (Fig. 9.7.5) or omnivores, but others seem to be strictly saprophagous or pollen-feeding.