NORSK ENTOMOLOGISK TIDSSKRIFT - Norsk entomologisk forening

50 Albert Lillehanzmer
Fig. 3. C. bifrons (Newman). Dorsal view of: A. The thorax of a
fullgrown male nymph, wing pads strongly reduced; B. The posterior
segments of a male nymph; C. The thorax of a full-grown female nymph,
normal wing pads.
Fig. 4. C. bifrotzs (New-man). The
posterior abdominal segments, of
an adult male, lateral view.
long and, more powerful than the male. The wings are normal.
The female C. bifrons is easily distinguished from the other
Capnia species in that the cell between Cu, and Cu, are quadrangular.
Whe11 the large stock of Capnia bifrons nymphs was found in
March-April in Saterbekken the pH value and the amount of
dissolved Ca differed somewhat from what Brinck eives for C.
bifrons localities in SkAne, the water in ~zterbekken bzing slightly
acetous with not much dissolved Ca. Toeether with C. biirons
many specimens of Leuctra hippopus ~ernFn~ were found, which,
according to Brinck (p. 188, fig. 43) would be the Plecoptera
species having the highest degree of association with C. bifrons.
One could therefore accept this as an indication that Szterbekken
constitutes a C. bifrons biotope. Brinck divides rivers and streams
according to the composition of species. In Szterbekken live some
of the species which are e u c o e n i c in rivers and streams in
South Sweden, and the composition does, for the greater part,
agree with what Brinck says about C. bijrons localities. However,
there is an admixture of species with a northerly occurrence in
Sweden. Especially nymphs of Diura nanseni (Kcmpny) are
found in great numbers. This makes Szterbekken, all the same,
differ somewhat from the usual C.bifrons localities in Sweden.
A work comprising the Plecoptera compounds in Szterbekken
will appear later.