The temporal dynamics in density, life histories, and emergence patterns were described for the first time for five Plecopteraspecies in tributaries of the Futaleufú River in Patagonia, Argentina. Benthic samples and adult collections were made in five loworder Nothofagus forested streams. Four species of Gripopterygidae; Aubertoperla illiesi, Notoperlopsis femina, Antarctoperlamichaelseni and Senzilloides panguipulli had simple, highly synchronized univoltine life histories. The austroperlid Klapopteryxkuscheli takes more than two years to develop. Emergence periods of most of the species were concentrated in late spring andsummer (October to February), which suggests seasonal and synchronized life histories. Most N. femina adults were collected inmid spring indicating this species emerged first, whereas S. panguipulli emerged last from January to April. Aubertoperla illiesishowed a slightly delayed emergence at the high elevation site (La Hoya Stream) when compared to a piedmont stream,suggesting that temperature was an important control. Although we were unable to describe the life history of Limnoperla jaffueli(Gripopterygidae) its adult emergence period was November to January. Life histories of Plecoptera species in the studiedstreams seem to have a high degree of seasonality at least at this latitude, and are possibly determined by predictable temperaturepatterns and discharge regimes. This first contribution on the life histories of Plecoptera species helps us to better understand thedynamics and functioning of pristine but fragile aquatic environments in Patagonia.

In this revision of the 25 French Protonemura, two new taxa are described : P. zhiltzovae sp. n. and P. ausonia padana ssp. n.Moreover, P. spinulosa (Navás 1921) is restored to the species level. Affinities, etymology, ecology and distribution are commentedon for each species. Identification keys and drawings are given for males and females. Finally, Protonemura distributionswithin the main French mountainous massifs are discussed.

73 species and subspecies are reported from the North West of the Iberian Peninsula, including 10 new taxa described in the last four years. 14 species are new for the Cantabrian Cordillera, 1 for Galicia, 9 for the Sierra de la Demanda and 2 for the Sierra del Moncayo. The systematic status of some species is modified: Protonemura pyrenaica pyrenaica and P. pyrenaica asturica are restored to specific level; Leuctra lusitanica is considered as a subspecies of L. lamellosa; Nemoura cinerea umbrosa is a valid subspecies of N. cinerea cinerea. The stonefly faunistic lists of the Cantabrian Cordillera, Galicia, Demanda and Moncayo are updated. Species distribution patterns and faunistic relations with the neighbouring regions are analyzed. Classification and ordination analyses based on species presence, enable identification of bioclimatic and biogeographical patterns of Plecoptera distribution in the North of the Iberian Peninsula.

Emergence traps were operated over three years in a stream near Lunz in southwestern Lower Austria, to find out the differences between eight types of traps. Trichoptera, Plecoptera, Ephemeroptera, Simuliidae, Limoniidae and Empididae were compared quantitatively as whole groups. Trichoptera, Limoniidae and aquatic Empididae were compared at species level. Except for the expected statistical variation, there was wide variation in the number of specimens between groups and species, and also between the trap types, to such a degree that the emergence method appears to be of limited value for productivity or other quantitativestudies. The total catch of insects caught in the traps, consisted of freshly emerged adults, aged ovipositing females and many other insects (including terrestrial ones) which entered the traps in unknown ways. The variation may depend on the biology and behaviour of the insects, on the design of the traps and on an unknown number of other factors.

A taxonomic and biogeographic study of the Pyrenean Leuctridae is presented. Keys for males and females of 32 Leuctridaespecies are given.The male of Pachyleuctra bertrandi Aubert, 1952 is described completely for the first time ; P. ribauti Despax, 1929 is restoredas a valid species ; Leuctra ariega Pardo & Vinçon, 1995, L. garumna Vinçon & Ravizza, 1996 and L. prima Kempnyi,1899 are new for the Iberian Peninsula ; L. espanoli Aubert, 1956 is new for the French Fauna.

Nous avons analysé la distribution régionale de 147 espèces appartenant aux 4 ordres d'insectes aquatiques les mieux connusdans le Sud-Ouest de la France - Ephéméroptères, Plécoptères, Trichoptères, Coléoptères Elmidae et Hydraeniidae -, afin d'établirune classification des cours d'eau basée sur des associations spécifiques au sein du réseau hydrographique Adour-Garonne(116 000 km2). La distribution spatiale des espèces a été précisée par des Analyses Factorielles des Correspondances (AFC), etles noyaux d'affinité entre espèces et/ou stations ont été recherchés par la Méthode des Nuées Dynamiques. Six zones ont étédéfinies, ainsi que leurs peuplements théoriques. Un intérêt majeur de telles classifications est que la stabilité spatio-temporelledes associations spécifiques peut être utilisée pour définir des sites ou des stations de référence, pour une surveillance biologiquedes rivières au sein d'une région ou d'une section longitudinale identifiée par un peuplement référentiel.

Aspects of the egg biology of the perlid stonefly, Dinocras cephalotes (Curtis), were studied experimentally. Development under constant laboratory conditions did not differ from development under variable field conditions. Exposure to 4°C, the lower threshold temperature for egg development, caused abrupt interruptions of embryonic development. Development was resumed after return to favourable temperatures, with an approximate two-week-delay. Up to six interruptions of egg development did not negatively affect hatching success, regardless of developmental stage at which disturbances occurred. However, the older embryos grew, the more rapidly development was resumed after a cold disturbance; embryos from fully developed eggs hatched even at 4°C, although this is too cold to support larval growth. While eggs at 4°C remain dormant and vital for long periods of time, eggs exposed to suboptimal temperatures (10°C) remain only temporarily dormant and eventually develop and hatch.D. cephalotes is assumed to satisfy its high thermal demand for egg development under harsh conditions, for example in arctic Scandinavia, by opportunistically using summer warmth and spreading embryogenesis over more than one year. I suggest that high cue temperatures required to initiate egg development in Scandinavian populations are adaptive and ensure that larvae in the Arctic hatch under favourable seasonal conditions.

Several new species of Plecoptera (Leuctra hexacanthoides, L. berthelemyi, L. thomasi, Protonemura culmenis, P. canigolensis) collected in the Pyrenees of France, Andorra, and Spain are described and illustrated. Protonemura brevistyla (Ris) and P. montana Kimmins are recorded from the Pyrenees for the first time.

Le développement larvaire des Plécoptères Leuctra hippopus Kempny, Siphonoperla libanica Alouf et Protonemura zernyi Aubert est étudié. Ces espèces colonisent des ruisseaux permanents du Liban. L. hippopus est hivernale univoltine ; S. libanica est printanière univoltine ; P. zernyi a une période de vol étendue de l'automne jusqu'au printemps avec un ralentissement des émergences au début de l'hiver. P. zernyi est probablement une espèce plurivoltine.

Le développement larvaire des 4 espèces de Plécoptères Capnia ? arensi Zhiltzova, Brachyptera galeata Koponen, Protonemura libanocypria Zwick et Isoperla libanica Aubert est étudié. Ces espèces colonisent un ruisseau temporaire du Liban. C. ? arensi est une espèce hivernale, B. galeata et P. libanocypria sont printanières, I. libanica est printanière tardive.

55 espèces de Plécoptères ont été recensées dans la vallée supérieure du Pô (Alpes Cottiennes, Piémont, Italie) où, pendant plusieurs années, nous avons prospecté méthodiquement 7 stations lotiques situées entre 2,020 et 550 m d'altitude.Après avoir indiqué brièvement les caractéristiques de la vallée du fleuve Pô et des stations d'échantillonnage, les répartitions altitudinale, saisonnière et géographique des espèces récoltées sont analysées. Les principales plécoptérocénoses rhéophiles sont déterminées et analysées en fonction des paramètres des biotopes et des données qualitatives et semi-quantitatives.

Eggs of the stoneflies Diura bicaudata and Arcynopteryx compacta, occurring in the middle-alpine vegetation belt, andDinocras cephalotes not recorded above the sub-alpine, reacted differently to the same temperatures. Those of D. bicaudata and A. compacta had a diapause during the winter. D. cephalotes eggs went into a stage of quiescence when the water temperature was lowered from 16° C to 8° C or below. They remained alive in this stage for about a year, but this quiescence could be broken at anay time when the eggs were transferred to 16 and 20° C.Freezing at -6° C followed by an increase in the water temperature led to a break in the diapause of A. compacta eggs after five months, but not of D. bicaudata eggs.Eggs of D. bicaudata began to hatch after nine months independently of previous freezing followed by an increase inwater temperature. Eggs of D. bicaudata held at a constant temperature of 1.5° C also began to hatch at the same timeas those kept at 8° or 16° C. However, the point of 50 % hatching was much delayed at 1.5° C.The egg diapause of A. compacta and D. bicaudata is an adaptation to areas with a severe climate typified by long cold winters and short summers. The quiescence period of D. cephalotes eggs enables the species to survive outside its normal distribution area.