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-.Occurrence and life cycle of Dinocras cephalotes(Curtis, 1827) (Plec. Perlidae) in North NorwayHELGE HURUHuru, H. 1987. Occurrence and life cycle ofDinocras cephalotes (Curtis 1827) (Plec.Perlidae) in North Norway. Fauna norv. Ser. B. 34, 14-18.Dinocras cephalotes (Curtis 1827) was registered very locally in tributaries of therivers Reisa and Lakselv and in the River Alta in northern Norway. Suitable habitatsfor the nymphs seem to be very scarce in these rivers.D. cephalotes has probably a 4 to 5 year life cycle in Alta River. Growth took placeonly during two to three months each year.It is supposed that D. cephalotes had a wider distribution in postglacial times beingconnected to the southern Scandinavian populations and that the more recent colderclimate has separated the northernmost populations from the southern ones.Helge Huru, University of Troms0, Troms0 Museum, N-9000 Troms0, Norway.INTRODUCTIONThe carnivorous stonefly Dinocras cephalo­tes (Curtis, 1827) is widespread in centraland western parts of Europe (lIlies 1978,Zwick 1981). In central Europe it occursmainly in mountain streams and riversFig. I. The distribution of Dinocras cephalotes inFennoscandia.Circles: Distribution of D. cephalotes according toBrinck 1949, Thomas 1969, Lillehammer 1974and Hermandsen 1979.Triangles: New records of D. cephalotes.Investigated area shaded.14(Schoenmund 1925, Kuhtreibe 1934, Aubert1946). The species is common in continentalparts of southern Norway and Sweden(Brinck 1949, Lillehammer 1974), but hasonly been registered in three rivers in westernNorway (Lillehammer 1974, Hermansen1979). In Scandinavia D. cephalotes is commonnorth to 66° N (Brinck 1949, Ulfstrand1968b, Lillehammer 1974, Koksvik 1976),and is registered very sporadic north of 66°N, Fig. 1 (Thomas 1969, Lillehammer 1974).It has not yet been found in Finland (Meinander1980). High temperature requirementsto initiate egg development (Lillehammer1986) limit its occurence in northernlatitudes.This paper deals with the distribution andlife cycle of D. cephalotes in the northernmostpart of Norway.MATERIAL AND METHODSBottom fauna were collected in twenty watercoursesin northern Norway. (Fig. I, 2)between 1978-1984, using the standardtravelling kicking method (STKM, Pollard1981). Aquatic invertebrates were collectedwith a net which usually had mesh size 500/-Lm. In Alta River, a net with mesh size of250/-Lm were used. In the localities, several abioticand biotic parameters were measured. InAlta River, nymphs were sampled four to fivetimes/year over three years. In the riversLakselv and Reisa, nymphs were sampledFaulUJ norv. Ser. B, 34: 14-18. Oslo 1987.