Full-text - Norsk entomologisk forening

Norwegian stone/lies IT 235
Rogaland and Vestfold. In mountainous areas
it was taken at 1100 m a.s.l. in the Low­
Alpine belt. The species is one of the most
common stoneflies in the lower parts of
southern Norway and may be one of the
species dominating the stonefly fauna of
small streams. However, it seems to be rare
in stream sections where there is much silting.
Brachyptera risi was taken both in northern
and southern Sweden, and according to Brinck
(1949) the species is eucoenic in southern
rivers. It is not recorded from Finland.
Fam. Nemouridae
In this family the three Amphinemura, six
N emoura and the two Protonemura species
are all herbivore, but they show great differences
in distribution and dependence on
environmental factors.
Amphinemura borealis (Fig. 38) has been
taken in both southern and northern Norway.
It is recorded over most of southern Norway
in both small and large streams, although
most numerous in large rivers such as the
Glama and the Suldalslagen where silting
occurs with fine substrata among the stones.
It has not been taken above the coniferous
tree line. In the north the species has also
been taken in the Sub-Alpine belt, bilt it is
only common in the coniferous forest area of
Pasvik, where it is numerous in both small
streams and large rivers. It is also found in
lakes in this area. The species seems to prefer
certain substrata at least outside the area
which seems to be optimal, the Pasvik area.
The species is found both in southern and
northern Sweden, but is according to Brinck
(1949) eucoenic in northern rivers.
Amphinemura stand/ussi (Fig. 39) also occurs
in both southern and northern Norway,
although absent in some coastal areas. It is
often numerous and is one of the highest occurring
species. At high altitudes it is numerous
in the outlets of lakes. The highest locality
was in the Middle-Alpine belt at 1465 m a.s.l.
in 0vre Heimdal. The species occurs on stony
substrata in small and large streams, rivers
and, at higher altitudes, in lakes and their
outlets. In Sweden (Fig. 40) the species has
been taken both in the southern and northern
parts of the country.
Amphinemura sulcicollis (Fig. 40) is the
commonest species in this genus, and has been
taken all over Norway. It is also common
and numerous in the coastal areas. This
species may also be common in the Sub­
Alpine belt and it has been taken up to 1100
m a.s.!., in 0vre Heimdalen. The species is
common in small and large streams and in
rivers. Amphinemura sulcicollis also occurs
in lakes both in southern and northern Norway.
In the south it has been recorded from
lowland lakes such as Tyrifjorden and from
high altitude lakes such as 0vre Heimdalsvatn.
In Sweden it occurs in all parts of the
country (Brinck 1949).
N emoura arctica in Norway seems restricted
to Troms and Finnmark (Fig. 41). The species
occurs in small and large streams, in
lakes and outlets, both in places with stable
stone substrata and places with much fine
sand and an unstable bottom. At higher altitudes
(Middle-Alpine belt) the species may
be the sole plecopteran species and in such
localities can be very numerous. In Sweden
it has been taken as far south as the River
Vindeliilv, Swedish Lappland (Ulfstrand
1969).
N emoura avicularis (Fig. 42) has been collected
in northern and southern Norway, but
not in western Norway. In eastern Norway
it occurs both in the coastal areas and in the
mountains. In 0vre Heimdalen it has been
taken in the Low-Alpine belt at heights of
1300 m a.s.l. In both the north and south it
has been found in small and large streams,
rivers and lakes in the lowlands and at higher
altitudes. In streams it seems to prefer a slow
current and an unstable substratum with
silting, and has been collected in streams with
fine sand as substratum. The species is recorded
from both southern and northern
Sweden (Brinck 1949).
N emoura cinerea (Fig. 43) is widespread
in Norway, both in the south and the north,
and is common in the coastal areas and in
the mountains. In 0vre Heimdal it was taken
in the Middle-Alpine belt at a height of
1465 m. In streams where there is a rich
stonefly fauna, the species is scarce, but where
there only are a few species present N emoura
cinerea may be numerous, as is the case in