(Meigen, 1818)
Body
Medium sized larvae up to 8.5 mm long. A very shallow hump is present on the 11th segment. The L2 setae on the abdomen are fan-shaped Microsp app L2 pict. The posterior parapods bear about 75 simpel claws Microps apposit claws (Klink, 1982a; Wiederholm, 1983).
Head
The headcapsule is pale and the S3 is simpel.
Antenna
The antenna stands on a pronounced pedestal with a small apical spur Mips small spur ant pedestal consists of 5 segments. The basal segment is 220 - 365 µm long. Segment 2 is cylindrical and longer than the remaining segments. The small Lauterborn organs distally on segment 2 with a very long pedestal.
Mentum
The mentum has a crenate median tooth and 5 pairs of lateral teeth Micropsectra mentum. The ventromental plates are close together medially and wider than the mentum.
Labrum
SI is a comb, SII is serrate with a large number of teeth and labral lamellae a single plate with 26 - 32 apical teeth. The pecten epipharyngis consists of 3 scales with distal teeth. The premandible with 2 teeth Mips labrum pe premandible.
Mandible
The mandible with a dorsal tooth, one apical tooth and 3 inner teeth all brown. The pecten mandibularis is present and seta interna with branches.
Differential characteristics
Distinctive for most species is the small apical spur on the antennal pedestal Mips small spur ant pedestal. M. bidentata with a large projection Mipsbi large distal proj ant p can be separated from Tanytarsus gr. brundini by the larger number of claws and Micropsectra fusca (with a bare pedestal and a distinct hump on the 11 segment) can be separated from Krenopsectra by its much larger size (10 mm vs 5 mm in Krenopsectra).
M. junci can be separated from the other Micropsectra by:
The fan-shaped L2 on the abdomen Microsp app L2 pict, labral lamellae with 26 - 32 teeth and the pale headcapsule.