Pharceonus Spangler & Santiago-Fragoso, 1992 Figs 5, 8, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87

Diagnosis.

The genus Pharceonus can be distinguished from all other genera of Laraine Elmidae that occur in South America by its small size and distinctive pronotum. All Pharceonus species are small (3.1-4.3 mm), but generally larger than the similar genus Phanocerus, in various shades of medium to dark brown, with a pronotum that has a distinctive transverse bisinuate impression at the apical third and a transverse, bisinuate impression subbasally (Fig. 83). These two impressions form two gibbosities on the basal two thirds of the pronotum (Fig. 83).

Distribution. Pharceonus species occur throughout southern Central America and northern South America, from Costa Rica south to Peru (pers. obs.).

Habitat. Members of this genus can be found on roots and woody debris in small to medium forested streams and seeps, as well as in the benthos, among gravel and sometimes on on rocky substrate (Spangler and Santiago-Fragoso 1992).