SUMMARY.A quantitative funnel‐trap sampler for air‐breathing aquatic insects is described. Performance tests with special reference to adultGlaenocorisa propinquaare presented. Abundance was calculated from pilot surveys with the funnel‐trap sampler during 1976 and compared with results from a trial with the capture‐recapture method. The influence of temperature on the frequency with which adultGlaenocorisa propinquarenews the bubble gilt was m