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Cicindela hirticollis Say 1817 is associated with shoreline and riverine sand deposits and is widely distributed in North America. Geographic variation in this species was analyzed by multivariate analysis of size, elytral markings, and color data obtained from some 4000 specimens from 75 sites throughout the species distribution. Eleven subspecies are recognized and discussed: C.h. hirticollis Say, gravida LeC., ponderosa Thorns., abrupta Csy., rhodensis Calder, corpuscula Rumpp, shelfordi, athabascensis, coloradula, couleensis, and siuslawensis Graves. Possible Pleistocene réfugia, and redistribution of the species following continental glaciation are discussed. Theoretical advantages of certain variants in particular climates or on certain substrates, are considered. Cicindela hirticollis has been eliminated or is endangered in many of its former habitats due to human activities.Five new subspecies are described: C. h. shelfordi (type locality: Guthrie, OK) which inhabits the Great Plains region; C. h. athabascensis from the Lake Athabasca Sand Dunes of Saskatchewan and Alberta; C. h. coloradula from the Little Colorado River, AZ; C. h. couleensis (type locality: Vantage, WA) which is distributed in the Columbia–Snake river system of Washington, Oregon, and Idaho; and C. h. siuslawensis (type locality: Florence, OR) which inhabits the Pacific coast of Oregon and Washington.

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Epipsammic diatom communities were sampled and quantijied bimonthly from June 1983 to April 1 9 8 5 at four sites i n a small brook i n northwest Ohio. The primarj objective was to determine the extent of temporal and spatial variability i n the epipsainmon. The f o u r sites, approximately 250 tn apart, dzffered in current velocitj, illumination and the amount of sand-associated detritus. Diatoms were signijicantly more abundant in the portion of the brookjlowing through a n unshaded marsh than at three heavily shaded sites located upstream. Fragilaria leptostauron (Ehr.) Hust. and Achnanthes lanceolata var. dubia Grun. dominated the epipsammic assemblage at all sites throughout the entire studj period. Onlj Meridion circulare (Grev.) Ehr. displajed a marked seasonal distribution. Although the same species were generallj found at all sites, there were suj'icient differences in relative abundance that Communities could be discriminated according to site. Using two canonical sariate axes, all 48 samples were correctly assigned to their proper sampling site based on communitj composition. Data f r o m this epipsammic assemblage support the idea developed from the river continuum concept that species comprising riverine benthic assemblages continuallj persist and rarely become completelj absent.