NORSK ENTOMOLOGISK TIDSSKRIFT - Norsk entomologisk forening

Investigations regarding the Plecoptera fauna in Rogaland 107
found of adults and of nymphs at an early stage of development
as well as nymphs ready to emerge where the skin was loosened
in such a way that the genital organs became visible. These
species were determined, at first, by nymphal characters; thereafter
the nvm~h skin was removed and the insect. readv to
emerge, wa; then out and determined by its adult LharaGers.
Nymphs of the two Isofierla species ready to emerge do not have
visible genital organs and one must therefore dissect the dental
field on the male penis. Leuctra nigra was found in most examples,
as adult and one nymph only. Nemurella fiicteti was found as
nymph only, not ready to emerge; this species was determined
bv nvm~hal characters onlv. Below. additional information of the
cgarictirs of species are in the text where I have thought
it necessary to earlier descriptions. Some of my examples show
minor divergencies in the genitals. Drawings are made by means
of a drawing-mirror. Mention is made where nymphs ready for
emergence can be determined by the imago characters.
The material has been fixed with 80% alcohol and kept in
70% alcohol. This also applies to imagines where a comparison
of genitalia of dried individuals is very difficult. Length measurements
were carried out on materials kept in alcohol, and indicate
the length of the body only without feelers and cerci.
14 species were found, besides some nymphs which could not be
determined with certaintv. Nearlv half of the 29 known Norwegian
species were accordingly found in the areas investigated.
It was seen that the Plecoptera together with the chironomides
was the dominating insect group in the rivers and streams examined.
This differs from what is stated of investigations in England,
Sweden and Germany where Ephemeroptera dominate
about to the same degree as Plecoptera in this work (Neil 1938,
Badcock 1954, Miiller 1954, Illies 1961).
Our knowledge of Plecoptera in West Norway is based upon
information from Brekke 1941. The synonyms he used are
included in the systematic arrangement below. In the material
3 species are new to West Norway and 10 species are new to
Rogaland.
Abbreviations: Kn = N. Knaben: M.O. = M. Opheim; W.M.S. = W. M.
Schayen; M = Th. Miinster.
Family T a e n i o p t e r y g i d a e Klaprilek, 1905
Genus Brachyptera Newport, 1851
Brachyfitera risi (Morton 1896). (Brekke: TaenioPteryx risi
Morton).
Earlier records in West Norway: Bergen HOy (Kn) and in
Lardal SFi (M.O.).