Description of the larva of Holocentropus insignis Martynov 1924 (Trichoptera: Polycentropodidae) with notes on biology and distribution.

The hitherto undescribed larva of Holocentropus insignis Martynov 1924 was collected in Denmark, the Netherlands, and Finland. Based on larval morphology and DNA association with adults, we were able to distinguish the larva of H. insignis from other Holocentropus species known to occur in Europe and confirm its identification. We provide morphological features to separate H. insignis from the other known species within the genus and give an updated key to all known European larvae of Holocentropus. Extensive notes on the life cycle, biology, and distribution of H. insignis are given.