The seventh in a series on the Leptophlebiidae (Ephemeroptera) of New Caledonia, this papers treats three new genera(Paraluma, Oumas, and Amoa) and 12 new species. For Paraluma gen.n., the type species P. cancellata sp.n., P. triangularissp.n., P. gilva sp.n. and P. minuta sp.n. are described from male and female imagos and nymphs, P. pulla sp.n. from male imagosand nymphs, and P. maculata sp.n. from male and female imagos. For Amoa gen.n., the type species A. fronini sp.n., A. subsolanosp.n. and A. orthogonia sp.n. are described from male and female imagos and nymphs, A. cressonensis sp.n. from nymphsonly and A. hebes sp.n. from the male imago only. Oumas orbis gen.n. sp.n. is described from male and female imagos andnymphs.

64 échantillons collectés par le Professeur Th. Monod en 1971 dans les eaux intérieures des Açores lors d'une missionà terre de la campagne Biaçores ont été examinés. Dix sept espèces et sous-espèces ont été identifiées dont onze nouvelles pour les Açores. Eucyclops agiloides açorensis et Metacyclops mendocinus insulensis sont décrites comme sous-espèces nouvelles. La présence des différentes espèces reconnues dans ces îles, ainsi que leur répartition géographique, sont commentées.

The nature of soil-water interactions is discussed in the context of both soil formation and drainage water chemistry. The interacting factors regulating drainage water chemistry are then briefly considered, including soil type and parent material, soil atmosphere CO2 concentration, hydrological pathways, soluble salts, topography, climate and biotic effects. Based upon these factors, some sites in NE Scotland thought to be highly susceptible to water acidification are examined, and the low pH of their waters is confirmed. The acidity trends of two superficially similar streams apparently less at risk are compared, and the differences explained in terms of sub-surface soil characteristics. The possible impacts of both afforestation and of acidifying pollutants on water pH are considered briefly where appropriate.