The threshold for proboscis extension to sucrose stimulus of a single sugar receptor on different labellar hairs was elevated by raising blowflies on higher concentrations of sucrose. The reaction time was defined as the duration from stimulus of a single sugar receptor in the LL-type hair until occurrence of proboscis extension. Reaction times at the threshold concentrations of sucrose did not change among blowfiles raised on different sucrose levels. The average value is about 0.35 s. Relationship of the average number of impulses during 0.35 s to log median acceptance thresholds of sucrose for proboscis extension was linear.