The North and Central American species formerly placed in the genus Mycetoporus are revised. Two genera are recognized, Mycetoporus Mannerheim and Ischnosoma Stephens, each with 18 species. The morphological and historical basis for this division is discussed. Ten species of Mycetoporus are described as new: bipunctatu, floridensis, impunctatus, neomexicanus, nidicola, pacificus, rufohumeralis, segregatus, smetanai, and triangulatus. Ten species of Ischnosoma are described as new: arizonense, ashei, costale, durangoense, fimbriatum, hermani, lecontei, mexicanum, pecki, and suteri. Mycetoporus boreelus J. Sahlberg, a species restricted to the Palearctic region, is removed from synonymy with M. nigrans Mäklin and Mycetoporus insignis Mäklin is found to be a junior synonym of M. americanus Erichson. Mycetoporus discalis, M. punctatissimus, and M. punctulatus, all species described by Hatch (1957), are transferred to the genus Bryoporus subgenus Bryophacis and the name Tachinus humidus Say is treated as a nomen dubium in the genus Mycetoporus.The usage of the generic names Mycetoporus Mannerheim and Ischnosoma Stephens is discussed. The North American species of the genus Mycetoporus are placed in six species groups and those of the genus Ischnosoma are placed in four species groups.A neotype is designated for Mycetoporus nigrans Mäklin and lectotypes are designated for M. americanus Erichson, M. insignis Mäklin, M. tenuis Horn, M. lucidulus LeConte, M. consors LeConte, Ischnosoma pictum (Horn) and I. flavicolle (LeConte). The following species were transferred from Mycetoporus to Ischnosoma and are new combinations: pictum Horn, splendidum Gravenhorst, flavicolle LeConte, virginiense Bernhauer, coxale Sharp, hospitale Fall, californicum Bernhauer and Schubert, and curtipenne Bernhauer.All genera, species groups, and species are described and the species are illustrated with line drawings and scanning electron photomicrographs. Keys are provided to distinguish the genera Mycetoporus and Ischnosoma and for all the species in each genus. The New World distribution of each species is mapped. The biology of each species, if known, is discussed.

The classification of the nine world species of Pytho Latreille is reviewed by study of adult, larval, and pupal stages. Keys are provided for separation of species in these three life stages. Taxonomic changes (senior synonym in brackets) include synonymy of P. fallax Seidlitz 1916 [= P. niger Kirby 1837]; P. americanus Kirby 1837 [= P. planus (Olivier 1795)]; P. deplanatus Mannerheim 1843 is transferred from a junior subjective synonym of P. depressus (Linnaeus 1767) to a junior subjective synonym of P. planus (Olivier 1795). Lectotype designations are provided for the following: P. seidlitzi Blair 1925; P. nivalis Lewis 1888; P. niger Kirby 1837; P. fallax Seidlitz 1916; P. abieticola J. Sahlberg 1875; and P. americanus Kirby 1837. Eight larval stage, and 12 adult stage characters were selected for cladistic analysis. Lacking out-group material, pupal characters were not analysed. Character states were polarized using a generalized out-group composed of the three other genera of Pythinae (all monobasic). Phylogenetic analysis based on these 18 characters suggests four monophyletic species-groups: P. seidlitzi group (P. seidlitzi Blair — North America); P. kolwensis group (P. strictus LeConte – North America, P. kolwensis C. Sahlberg —Fennoscandia and the U.S.S.R., P. nivalis Lewis — Japan); P. niger group (P. niger Kirby — North America, P. abieticola J. Sahlberg — Europe, P. jezoensis Kôno — Japan); P. depressus group [P. planus (Olivier, 1795) — North America, P. depressus (Linnaeus, 1767) — Europe and the U.S.S.R.]. Larval stage synapomorphies are relatively more important in defining the species-groups than are those of the adult stage. The ancestor of Pythidae may have been associated with Coniferae as early as the Jurassic. The common ancestor of Northern Hemisphere Pythinae became isolated upon Laurasia once separation from Gondwanaland occurred near the end of the Jurassic. Two of the species-groups have similar disjunctions in North America, Europe, and Japan. The relatively eastern distributions of the North American member of each suggests that the ancestor of each species-group was Euramerican, and underwent vicariance with the opening of the North Atlantic in the Middle Cretaceous. The present distribution of both species-groups is thought to have been caused by the same vicariant event. The ancestor of the P. depressus group, which is presently circumboreal, was probably widespread and could have been Asiamerican in distribution. In the middle to late Tertiary, evidence suggests that Beringia was covered with coniferous forest, and the ancestor of the P. depressus group probably extended across this land bridge. Final separation between any North American and European/Asian species occurred in the Late Miocene or Pliocene, when a cooling climate made possible the evolution of treeless tundra in the north.

The 183 species of Lepidoptera recorded from Bermuda are discussed with respect to their world distribution, origin, long-range dispersal capability, host plants, nomenclature, and the circumstances of their occurrence in Bermuda; most are illustrated. Fifty-nine species are reported from Bermuda for the first time; Oenobotys invinacealis Ferguson (Pyralidae) and Tetanolita mynesalis inaequalis Ferguson (Noctuidae) are described as new. Four new genus–species combinations and four new synonymies are proposed.The Bermuda islands have a distressed fauna dominated by introduced pest species and migrants from the North American mainland and Caribbean Region. About 125 of the 183 recorded species are thought to be established residents; the remainder are assumed to be vagrants. Of approximately 50 resident species identified as probably indigenous, 11 species and three subspecies are endemic, and one of these, Semiothisa ochrifascia (Warren), is believed extinct.All Bermudian Lepidoptera are of American origin except the few introduced Old World species that are nearly cosmopolitan. Like Norfolk Island, Australia, Bermuda has a supersaturated lepidopterous fauna — more recorded species than its land area might support, which can be explained only by a high incidence of migrants and transients. This migratory component is explained relative to long-range movements of the same or congeneric species elsewhere; and hypotheses are proposed concerning the natural history of long-range dispersal in eastern North America and the ability of these moths to reach Bermuda. From a list of 113 species of Lepidoptera identified as frequent south–north migrants on the mainland, 76 are recorded from Bermuda. These include 38 of the 40 best-known cutworm moths of the eastern United States. It is argued that such moths reach Bermuda repeatedly without man's assistance and must regularly travel similar distances in North America.

Genera and previously described species of Nearctic Scythrididae are revised for the first time, based on the study of adult structures. About 90 percent of the Nearctic fauna known in collections consists of undescribed species. The supraspecific taxa treated in this work encompass less than half of the Nearctic species diversity. Only six new species are described, all within the largest and structurally most diverse genus. The status of all nominal species is revised. Valid species are redescribed and their features illustrated. General problems in the systematics of the Scythrididae are discussed. A description of adult features of the family Scythrididae is providad. Extra-limital genera are briefly reviewed. A key to the Nearctic genera and informal supraspecific lineages is provided.Six genera, including three new, are treated: Areniscythris Powell, 1976, Arotrura Walsingham, 1888, Asymmetrura gen. nov., Neoscythris gen. nov., Rhamphura gen. nov., and Scythris s. str. Hübner, [1825]. Areniscythris includes a single described species, Areniscythris brachypteris Powell, but is defined more broadly to account for a number of undescribed species. Arotrura is divided into nine informal species groups with the following included species: Arotrura atascosa sp. nov., Arotrura balli sp. nov., Arotrura divaricata (Braun) comb, nov., Arotrura eburnea Walsingham, Arotrura formidabilis sp. nov., Arotrura hymenata sp. nov., Arotrura longissima sp. nov., Arotrura oxyplecta (Meyrick) comb, nov., Arotrura powelli sp. nov., and Arotrura sponsella (Busck) comb. nov. Asymmetrura includes: Asymmetrura albilineata (Walsingham) comb. nov., Asymmetrura graminivorella (Braun) comb. nov., Asymmetrura impositella (Zeller) comb. nov. and type species, Asymmetrura matutella (Clemens) comb, nov., Asymmetrura reducta (Braun) comb, nov., and Asymmetrura scintillifera (Braun) comb. nov. Neoscythris includes: Neoscythris confinis (Braun) comb, nov., Neoscythris euthia (Walsingham) comb. nov., Neoscythris fissirostris (Meyrick) comb. nov. and type species, and Neoscythris planipenella (Chambers) comb. nov. Rhamphura includes: Rhamphura altisierrae (Keifer) comb, nov., Rhamphura ochristriata (Walsingham) comb. nov. and type species, Rhamphura perspicillella (Walsingham) comb. nov., Rhamphura suffusa (Walsingham) comb. nov., and the extra-limital Rhamphura immunis (Meyrick) comb. nov. from Peru. Scythris s. str. includes: Scythris immaculatella (Chambers) rev. stat., Scythris limbella (Fabricius), Scythris mixaula Meyrick, Scythris trivinctella (Zeller), and Scythris ypsilon Braun. A further eight species are phylogenetically distinct from Scythris s. str. but provisionally are only assigned to five informal monophyletic lineages until their cladistic relationships are more firmly established. These are: the Scythris basilaris lineage including Scythris basilaris (Zeller), Scythris eboracensis (Zeller), and Scythris fuscicomella (Clemens); the Scythris interrupta lineage including Scythris interrupta Braun; the Scythris inspersella lineage including Scythris inspersella (Hübner) and Scythris noricella (Zeller); the Scythris anthracina lineage including Scythris anthracina Braun; and the Scythris charon lineage including Scythris charon Meyrick. Three species are incertae sedis: Scythris inornatella (Chambers) comb, nov., Scythrispilosella (Zeller), and Scythris piratica Meyrick.Coleophora albacostella Chambers and Coleophora inornatella Chambers are transferred from the Coleophoridae. Scythris arizoniella (Kearfott) is transferred to the Coleophoridae [Coleophora arizoniella (Kearfott) comb. nov.].The following new synonymy is proposed: Colinita Busck, 1907 = Arotrura Walsingham, 1888; Gelechia aterrimella Walker, 1864 and Scythris epilobiella McDunnough, 1942 = Scythris inspersella [Hübner, (1817)]; Scythris magnatella Busck, 1904 = Scythris noricella (Zeller, 1843); Scythris pacifica McDunnough, 1927 = Scythris immaculatella (Chambers, 1875); Coleophora albacostella Chambers, 1875 and Scythris hemidictyas Meyrick, 1928 = Neoscythris planipenella (Chambers, 1875).A cladistic definition of the family is presented for the first time. The monophyly of the Scythrididae is supported by the following synapomorphies: very narrow ductus bursae, broad ductus seminalis anastomosed with the oviduct and the corpus bursae, lack of signum, unique shape of the apophyses of the metathoracic furca, tarsomeres 1–4 with two subapical spurs, aedeagus ankylosed, and origin of forewing veins R4 and R5 on a common stalk with R4 extended to the costa and R5 to the termen. Relationships of the Scythrididae within the Gelechioidea are discussed. Based on the cladistic analysis of 52 structural characters, phylogenetic relationships of supraspecific taxa are inferred. Two cladograms, one for the genera and one for the species groups of Arotrura, are presented and used in deriving the classification.

North American members of the genus Plateumaris Thomson, 1859, are revised; 17 species are recognized and 23 taxonomic changes are made in their classification. Plateumaris balli and P. schaefferi are described as new species. Names elevated from subspecies to species rank are P. robusta (Schaeffer) and P. frosti (Schaeffer); P. aurifera (LeConte) is revalidated, removed from junior synonymy with P. wallisi (Schaeffer); Donacia idola Hatch is considered a junior subjective synonym of P. dubia (Schaeffer); D. pyritosa LeConte is considered a junior subjective synonym of P. pusilla (Say); an altered species concept is transferred to P. flavipes (Kirby), with D. wallisi Schaeffer as a new junior subjective synonym, and P. flavipes of authors is correctly named P. shoemakeri (Schaeffer); D. longicollis Schaeffer and D. vermiculata Schaeffer are considered new junior subjective synonyms of P. neomexicana (Schaeffer); D. flavipennis Mannerheim is considered a junior subjective synonym of P. germari (Mannerheim); D. rufa Say (not D. rufa of authors) is transferred to Plateumaris from Donacia, with an altered species concept applied to it, and D. affinis Kirby, D. sulcicollis Lacordaire, D. chalcea Lacordaire, D. kirbyi Lacordaire, and D. jucunda LeConte are considered new junior subjective synonyms of P. rufa (Say). The taxon previously considered D. nitida Germar (sensu Schaeffer) is redescribed as P. schaefferi; P. nitida (Germar) is a valid, different species, with D. emarginata Kirby, D. juncina Couper, and D. pacifica Schaeffer considered new junior subjective synonyms of P. nitida. Neotypes are designated for Donacia pusilla Say, Donacia rufa Say, Donacia metallica Ahrens and Donacia nana Melsheimer; lectotypes are designated for all other names, where necessary.Among Palaearctic taxa, Plateumaris morimotoi Kimoto and P. hirashimai Kimoto are considered new junior subjective synonyms of P. weisei Duvivier, and P. sachalinensis Medvedev, P. orientalis Shavrov and Donacia mongolica Semenov are considered probable junior subjective synonyms of P. weisei; P. sulcifrons Weise and P. affinis (Kunze) and its synonyms are considered new junior subjective synonyms of P. rustica (Kunze); P. caucasica Zaitsev is considered a probable junior subjective synonym of P. roscida Weise; P. discolor (Panzer) (and its synonyms) and P. lacordairii (Perris) are considered junior subjective synonyms of P. sericea (L.); new P. obsoleta Jacobson and P. socia Chen are considered probable junior subjective synonyms of P. sericea.Based on phylogenetic analysis, five species groups are recognized, the P. braccata group (two species), P. rufa group (five species), P. pusilla group (eight species), P. shoemakeri group (four species), and P. nitida group (seven species). The current subgeneric classification of Plateumaris is rejected. Characters hitherto used for subgenera of Plateumaris are shown to be either plesiomorphic or widely distributed among unrelated taxa; the relatively minor structural differences do not merit use of a subgeneric classification. Juliusina Reitter is a junior objective synonym of Plateumaris Thomson.Based on fossil and chorological data, the geographic history of donaciines in general and of Plateumaris in particular is deduced to be so old as to obscure correlations of more recent phylogenetic divergences with specific geologic events. The geographic history of even the most highly derived donaciine groups extends well into the Cretaceous. Therefore, explanations are speculative beyond the generality that donaciines have a long geologic history.

Since the first observation that plants contained protease inhibitors, as identified by their ability to inhibit vertebrate enzymes, it has been postulated that the presence of these substances was related to their phytoprotective abilities. However the following assumptions (1) that phytophagous insects use trypsin, and (2) that ingested inhibitors disrupt digestive proteolysis in insects, have not been adequately tested. Identification of non-tryptic enzymes, cathepsin B, D, and H in phytophagous Coleoptera and unique trypsin-like enzymes in Lepidoptera, indicates insect proteases may differ from their vertebrate counterparts. Putative inhibitor proteins inhibited vertebrate trypsin and chymotrypsin in vitro but had no effect on the trypsin- or chymotrypsin-like activity from the insect midgut. Feeding experiments with the European corn borer, Ostrinia nubilalis (Hübner), indicate that ingestion of inhibitors may not disrupt digestive proteolysis in vivo and the vertebrate trypsin inhibitor in corn may be ineffective as a phytoprotective strategy for this insect. Limitations and implications of ingested inhibitors for future pest control may depend on the origin of the inhibitor, as well as the insect's response.

Springs, or points of natural, concentrated groundwater discharge, may be located in river or lake beds, or below mean sea level along the coast, but many are found some distance from surface-water bodies. Spring water commonly represents rain or snow-melt that has entered the ground at a higher elevation a number of years earlier.Measured springwater temperatures in Canada range from very cold (−2.9 °C) to hot (82.2 °C). Thermal spring waters, with temperatures above the local mean-annual air temperature, have undergone geothermal heating during deep subsurface circulation in areas of high topographic relief. Hot springs (>37 °C) are therefore found only in mountainous areas, in Alberta, British Columbia, Yukon, and the Northwest Territories. Spring locations are commonly controlled by major folding or faulting, or both, in the bedrock strata.Reported pH values in Canadian spring waters range from strongly acidic to alkaline (2.8 to >10.0). Low pH values (<4.0) are associated with high contents of dissolved Fe (up to 2600 mg·L−1) and other heavy metals (e.g. Zn up to 177 mg·L−1), resulting from the oxidation of metal sulfides. Measured redox potentials (Eh) range from −252 to +683 mV. Negative Eh values are found in spring waters that contain dissolved H2S and S2−, produced by bacterial reduction of dissolved sulfate.Total-dissolved-solids contents of Canadian spring waters are reported to range from as little as 32 to over 75 000 mg·L−1. Chemical composition also varies widely. Major anions include bicarbonate (up to 5960 mg·L−1), sulfate (up to 17 520 mg·L−1), and chloride (up to 44 300 mg·L−1). Major cations include calcium (up to 1823 mg·L−1), magnesium (up to 1190 mg·L−1), sodium (up to 27 100 mg·L−1, and potassium (up to 1568 mg·L−1). The chemical composition of each spring water reflects the mineral composition of the rock types with which the water has been in contact, as well as its subsurface residence time. In simplified terms, Ca–Mg/HCO3 waters come from carbonate rock (limestone, dolomite), Ca/SO4 waters from gypsum or anhydrite, and Na/Cl waters from salt beds.Springwater temperature and composition can both show gradual (seasonal) and sudden (incidental) variations. In springs that show seasonal variations, maximum temperature and mineralization occur near the end of winter; minimum values commonly occur during snowmelt. Sudden variations in temperature, mineralization, and discharge rate can occur during periods of heavy rain, if cold, non-mineralized rainwater enters spring conduits. Earthquakes may cause sudden changes in discharge rates and suspended-solids contents, without affecting water temperature or chemical composition.Information on Canadian spring locations, and on their physical and chemical character, is still spotty. As detailed knowledge about springs can be useful in both ecological and water-supply studies, an effort should be made to expand and refine the existing database.

The major topographic features and river courses of the mid-Appalachian Mountains are geologically ancient. Small rheocrenes are numerous in carbonate valleys with macroinvertebrate assemblages typically dominated by peracaridans and sometimes gastropods, with subordinate abundances of bivalves, triclads, and insects. Springs were approximately rank ordered by temporal persistence, using size, catchment area, proximity to base level, and bedrock permeability factors as criteria. A 38-m2 rheocrene, Ell Spring, was sampled seasonally over a 2-year period for distribution and abundances of taxa. Physicochemical factors and rank order of ordinal abundances were stable the 1st year, but less so the 2nd year after a watercress cover was removed. Ell Spring is divided into nine distinct habitat patches. Some species distributions are strongly associated with patches and others are broader. Regionally, heterozygosity and allele frequency patterns of Gammarus minus (Amphipoda) are conditioned by latitude, indicative of the effects of Pleistocene glaciation, and by distance to regional master streams. These factors do not detectably influence the ordinal composition of macroinvertebrate assemblages. However overall invertebrate abundances and the ratio of non-insect orders (which are presumably less rapid colonists) to insect orders are greater in long-persisting than in frequently disturbed springs. The species assemblages of disturbed springs may be influenced by recent history as well as by water chemistry, substratum, and other equilibrium factors.

The thiophenes alpha-terthienyl and methyl-alpha-terthienyl are found in many species of the family Asteraceae and are highly phototoxic to mosquito larvae. These compounds and a synthetic analogue, cyano-alpha-terthienyl, controlled Aedes intrudens Dyar (Diptera: Culicidae) larvae at application rates between 10 and 40 g per hectare in field trials. These concentrations are similar to those currently used with chemical control agents. Piperonyl butoxide, a synergist used with pyrethrin, greatly increased the mortality of mosquito larvae at low application rates of the most potent phototoxin, cyano-alpha-terthienyl.Although we have demonstrated previously that these phototoxic defences are effective against some phytophagous insects, more recently we studied insects that are able to feed on a phototoxic plant, in order to examine modes of resistance to phototoxins. Chrysolina spp. (Coleoptera: Chrysomelidae) larvae are susceptible to phototoxicity but avoid it by feeding on Hypericum perforatum L. (Hypericaceae) at dawn and by hiding during the day. Chrysolina adults avoid phototoxicity by the presence of opaque cuticles that block the sunlight. First-instar larvae of Anaitis plagiata (L.) (Lepidoptera: Geometridae) avoid feeding on the glands that contain the phototoxin. Later-instar larvae feed on the entire leaf, yet are not susceptible to phototoxicity, indicating they have biochemical defenses against photo-induced damage.

The natural salt springs on Saltspring Island, southwestern British Columbia, originate from a source at least 1000 m deep and are distinct in chemical composition not only from the surrounding seawater but also from the groundwater-based salt springs on nearby Mayne Island. Spring water is approximately 2.2-fold more saline than average seawater and is characterized by having significantly higher levels of chloride, sodium, sulphate, silica, iron, alumina, and boron; similar levels of calcium, potassium, fluoride, and nitrogen; but less magnesium. The pH levels in different springs vary between 7.3 and 7.9, compared with pH 8.2 for average surface seawater. Near-surface water temperatures range from 7 °C in mid-winter to 16–21 °C in late summer.The flora and fauna that exploit this unique habitat are characterized by halophilic species known from other saline environments such as saline lakes, brackish water, beaches, and the intertidal zone. Organisms that have been isolated and identified include the following: seven species of bacteria, none of which depends exclusively on a saline environment; a blue-green alga that lives within the springs; an abundant filamentous green alga; and halophilic higher plants and grasses. Two species of spiders [Zelotes sp. (Gnaphosidae) and Pardosa sp. (Lycosidae)] are active in the salt-impregnated areas surrounding the springs.Collembola are represented by Anurida sp. (Poduridae); and insects by Saldula comatula (Saldidae, Hemiptera), the chironomids (Chironomidae, Diptera) Thalassosmittia marina plus two unidentified species, brine flies (Ephydridae, Diptera), and two unidentified cyclorrhaphan dipterans. Among the Hymenoptera, there are two species of Eupteromalus (Pteromalidae), Cyrtogaster capitanea (Pteromalidae), Urolepis rufipes (Pteromalidae), and Stigmus sp. (Pemphredonidae). Ants (Formica spp.) and yellowjackets (Vespula sp.) are frequent foragers in the immediate vicinity of the salt spring. There are three species of Coleoptera, Bembidion indistinctum (Carabidae), Ochthebius lecontei (Hydraenidae), and Thicanus mimus (Anthicidae). These insects are discussed in terms of their distribution within, and preference for, saline environments.

Leaves of the neem tree, Azadirachta indica A. Juss. (Meliaceae), have been used for centuries in India to protect stored grain from insect attack. Recent concern for the effects of synthetic insecticides on the environment and human health has provided the impetus for a reappraisal of the utility of neem derivatives as botanical crop protectants. Neem and its active principle, the limonoid azadirachtin, have several properties that are highly desirable for a natural insecticide. Azadirachtin is the most potent natural insect antifeedant discovered to date, suppressing insect feeding at concentrations of less than 1 part per million. Azadirachtin is also a potent insect growth regulator, which acts by disrupting molting and development, and interfering with reproduction in adult insects. These actions have been observed in over 90% of the more than 200 species of pest insects tested to date. Neem also has systemic action in some plants which could prove extremely valuable against stem- and root-feeding pests that are difficult to control. Finally, neem is essentially non-toxic to vertebrates, and in fact has a long history of medicinal use in southeast Asia.In the present paper we review our research aimed at developing a neem-based insecticide for use against pests of Canadian agriculture. We document the potent antifeedant action of azadirachtin in laboratory bioassays against the European corn borer, Ostrinia nubilalis Hübner, and the variegated cutworm, Peridroma saucia Hübner, and the molt-disrupting action of the compound in the migratory grasshopper, Melanoplus sanguinipes Fab., and the large milkweed bug, Oncopeltus fasciatus Dallas. Both antifeedant and insect growth regulatory activities of various samples of neem seed oil are shown to be correlated to azadirachtin concentrations in the oils. Field trials of an experimental neem insecticide conducted against pests of crucifers, corn, and potato in British Columbia, Ontario, and Prince Edward Island, respectively, indicate that the neem insecticide provides pest control as effective as or better than pyrethrum, the current botanical insecticide of choice for organic growers. The commercial prospectus for neem insecticides in Canada is discussed in light of our results.

Springs are especially useful for examining questions related to life history because they are widespread, and because they include not only the most predictable of freshwater habitats but also the most adverse (hot springs). Permanent springs tend to be stable environments, particularly in terms of temperature, discharge, and substrate. Extreme habitats such as hot springs can be ideal for studying biotic responses to environmental features because they vary little in certain factors and so do not conceal the mechanisms at work. This paper reviews the known life history and associated community traits of spring arthropods in terms of broad categories of selection forces thought to be acting in these habitats, and also examines the biotic consequences of stable environmental temperature. The data, although limited, show most support for the deterministic view of life history evolution in that traits of cold and hot permanent spring faunas tend to conform to those of K- and A-selected species, respectively. Nonconformities exist however, and data are totally lacking for springs that flow intermittently. A model continuum of spring types from the stable to the unstable and from the benign to the adverse is proposed which predicts the biological properties of communities living in little-studied spring types. The stable and/or adverse temperature regimens of springs are thought to impinge on many aspects of the biology of their faunas but most relationships (e.g. physiological, phenological) are based on data that are correlative, circumstantial, or laboratory based. Manipulative field tests are advocated to establish definite causative links. Wide scope exists for further research on the life history and community traits of spring arthropods.