The occurrence and movement patterns of adult insects along a forested springbrook near Flathead Lake, Montana, USA, were studied during three 15‐day periods from 19 June through 9 August 1985, using a two‐sided Malaise trap. Of the Plecoptera, numbers of males and gravid females ofMalenka flexuragravid females ofZapadafrigidaand total numbers ofParaperla wilsoniwere significantly higher for downstream‐flying adults during one to three periods. Of the Trichoptera, numbers of males ofAnagepetus debiliswere significantly higher for upstream‐flying adults during one period, and males ofLepidostoma cascadenseand gravid females ofL. spicatawere significantly higher for downstream‐flying adults during another period. In none of the 26 species examined in these three orders did females show a statistically significant pattern of upstream flight.