Small larvae, up to 4 mm long. Diagnosis based on undescribed species.
Antenna longer than head capsule, situated on a well developed pedestal; interpreted as 4 segmented with segment 2 with median unsclerotized articulated area, resembling intersegmental membrane; segment 3 much shorter than elongate whip-like segment 4. Blade extending to segment 3. Lauterborn organs small. Style as long as segment 3.
SI close to each other, bifid; SII more strongly developed; SIII very weak and close to the base of SII; SIV not visible. Only 1 bulbous chaeta present. Palatum strongly sclerotized. Pecten epipharyngis consisting of 3 scales. Chaetulae laterales of similar shape. Premandible with 1 apical tooth and a fine beard only visible with difficulty.
Apical tooth no longer than any of 6 inner teeth. Seta subdentalis a strong spine. Seta interna with 6-7 simple branches. Posterior seta on outer margin of mandible as long as mandible; anterior seta half the length.
Mentum with 1 broad median tooth; first 1-2 pairs of lateral teeth scarcely distinct; 3-4 pairs of pointed outer lateral teeth. Ventromental plate weak, not extending beyond outermost mental tooth; beard absent. Setae submenti strongly retracted towards occipital margin.
Maxilla palp short and broad with well-developed sensillae and setae. Galea short with well-developed lamellae. Setae maxillaris (all?) slender, simple and numerous.
Body with 3 thoracic segments. Parapods separate and bearing claws. Procerci sited close to each other, bearing 1 strong anal seta and 1 well-developed upper lateral seta. Supraanal seta strong, as long as posterior parapod. Anal tubules slender, slightly shorter than posterior parapod. Some body seta up to 0.5 segment length.
Larval Lopescladius are lotic in sandy-bedded streams and rivers of North and South America. The genus has previously been referred to as Cordites, an unavailable name.