Edwards, 1922
Body
Small larvae up to 3,5 mm long. The anterior parapods are separate. The two posterior parapods bear rows of claws. Procercus is present. Two pairs of anal tubules present. On the abdominal segments 1 - 7 the L4 bundle consists of appr. 10 seta that are up to 2 x as long as the segment (Hirvenoja, 1973 ).
Head
The head is dark (Hirvenoja, 1973).
Antenna
The antenna has a normal length and consists of five segments Cric ornatus antenna.
Mentum
The mentum has one median tooth and 6 pairs of lateral teeth. Median tooth < 2x the first lateral tooth. The second lateral tooth is reduced and partly fused with the first lateral Cric (I) intersectus mentum.
Labrum
The pecten epipharyngis consists of one compound scale Cric (Iso) pecten epiphary. SI is bifid. The premandible with 1 apical tooth (Hirvenoja, 1973).
Mandible
The mandible with a smooth inner side and wrinkled dorsal side. The apical tooth is shorter than the joined inner teeth.
Differential characteristics
The setal tufts of L4 Cric (C) 14 Cric (I) sylv body seta on the abdominal segments are distinctive for Cricotopus (and Orthocladius holsatus). C. tremulus and C. lygropus have no setal tufts however.
C. laricomalis can be separated from all other Isocladius by:
the L4 bundle on Segment 1 - 7 consisting of app. 10 setae twice as long as the segment.