Description of the aquatic larva and pupa of Paralichas trivittis (Coleoptera: Ptilodactylidae), with notes on its biology

1024 681 Stroud Water Research Center

Funk, D.H., and H. Fenstermacher. 2002. Entomological News 133:344–354.


The larva and pupa of Paralichas trivittis (Germar) (Ptilodactylidae: Cladotominae) are described and illustrated from spring seeps in Pennsylvania, USA. Larvae can be distinguished from all other known North American beetles by the presence of a highly modified 8th abdominal segment that is tapered posteriorly to form a spiracular siphon. Larvae were found in organic muck from woodland spring seeps and appeared to. be detritivores. Densities of up to 1400 larvae per square meter were observed. Pupation occurred near the larval habitat. Adults were found from June 6 to July 11. Notes on mating behavior, oviposition, egg development and faunal associations are provided.

While studying aquatic fauna in woodland spring seeps in southeastern Pennsylvania (Fenstermacher 2002), we found distinctive beetle larvae that were unidentifiable using existing taxonomic keys (e.g., Lawrence 1 991, White and Brigham 1996). Laboratory rearings established that the larva was that of Paralichas ( =Odontonyx ) trivittis (Germar). In this paper we describe and illustrate the larva and pupa, as well as provide notes on their biology.


NSF Award No. DEB-0096276. Title: LTREB: Stream ecosystem structure and function within a maturing deciduous forest. Duration: August 1998–July 2003.