NORSK ENTOMOLOGISK TIDSSKRIFT - Norsk entomologisk forening

114 Albert Lillehammer
Galea with hair on the inner side, and the lancina with a double
row of bristles as described by Brinck. The male nymphs ready
for emergence were examined and the penis was taken out. The
determination was difficult. The ength of the nymphs : 11-14 mm.
Family Chloroperlidae Okomoto 1912.
Family Cloroperlidae Okamoto, 1912
Genus Chloroperla Newman, 1836
Chloroperla burmeisteri (Pictet, 1841).
Earlier records in West Norway: Bergen HOy (Kn) og Leikanger,
Skjolden SFi (Kn).
Own records: Sauda and Suldal Ri. 10 9 2/6-64. In all 15
nymphs were found in May and June. The nymphs agree with
descriptions by Brinck and Hynes. Length 7-8 mm. The subgenital
plate of the adult female agrees closely with Zil'cova's
description (1964, Fig. 96,15). The colour was yellow to pale green.
Emergence was observed on 2 June 1964 between 1200-1300.
Length of the female 6-8 mm.
In working upon the material, it has proved possible to determine
most species of male nymphs ready to emerge, by both
nymphal and adult characters. Determinations, moreover, have
also been undertaken on adults. Only Nemztrella picteti was
determined solely upon its nymphal characters. This, however,
has very typical species characters and cannot be mistaken.
In the case of the two Isoperla species the dental fields on the
male penis were removed by dissection and the determination
was undertaken on the basis of these characters.
It seems that with plecoptera investigations, the greatest
weight should be placed upon obtaining material of nymphs
ready to emerge. It is frequently easier to obtain a rich material
of nymphs than of adults because the latter usually lead a more
secluded existence.
Analysis of the Material
The Plecoptera fauna in Suldalsligen is dominated in May by
Diura nanseni and Amphinemura borealis, in June by A. borealis,
in July by A. borealis together with Leztctra fztsca, in August by
L. fusca and in September and October by D. nanseni. Amphinemztra
sulcicollis can be said to be common in May, Leuctra
hippopus from February to May. The other species are rare
(cfr. Tab. 1).
' The plecAptera fauna in Storelva is dominated in May by
A. borealis and D. nanseni, in June by A. borealis whereas L.
fusca dominates in July and August. D. nanseni is common in