(Staeger, 1839)
Body
Medium sized larvae with a length up to 8 mm. Living larvae are brownish. No fringe of swimming hairs (Wiederholm, 1983; Moller Pillot, 1984a).
Head
The head length is 0.95 - 1.05 mm with a cephalic index of 50 - 65% (Wiederholm, 1983; Moller Pillot, 1984a).
Antenna
The antennal segments are all yellow and the antennal ratio is 3.4 - 4. The ring organ is situated at 0.6 - 0.7 of the height of the first segment. The second segment is normal and lacks a tuning fork (Wiederholm, 1983; Moller Pillot, 1984a).
Mentum
Dorsomentum without teeth.
Ligula and paraligula
Ligula with 5 brown teeth in a concave row. Paraligula with a long outer ad a smaller inner tooth Tri ligula paraligula.
Mandible
The mandible has a large basal and prominent accessory tooth Tri mandible.
Maxilla
The maxilla is short with an undivided basal segment.
Anal tubules
4 anal tubules which are longer than wide.
Posterior parapods
All claws on posterior parapods are yellow without teeth on their inner margin. The outer margin with a straight basal part, a blunt corner and a curved apical part Tri claws.
Differential characteristics
Within the Pentaneurini only Ablabesmyia, Telopelopia and Trissopelopia have a concave ligula Tri ligula paraligula, simpel claws on posterior parapods and a large basal mandibular tooth Tri mandible. Trissopelopia has a much larger head than Telopelopia (0.95 - 1.05 mm vs 0.60 - 0.70). Trissopelopia lacks the long 2 or more segmented maxilla of Ablabesmyia Abl phatta maxilla. Trissopelopia inhabits springs and cool streams, a biotope which lacks Telopelopia, an inhabitant of large rivers. Ablabesmyia is rarely seen in springs and cool streams.