Abstract: he functional response of the lady beetle, Menochilus sexmaculata （Fabricius） predating on the chrysanthemum aphid, Macrosiphoniella sanborni （Gillete） old nymphs fitted the model of HollingⅡ type well. However, the predation was affected by temperature, vessel space and prey density. In the same temperature treatment, the higher of prey density was, the larger of predation number was found and the lower of finding efficiency was observed. In the range of 15℃-25℃, the predation number increased with the increasing temperature. However, in the range of 25℃-35℃, the predation number decreased with the increasing temperature. At 25℃, predation number was the highest, which was 392.1 capita with anaverage number of 95 capita per day. The relationship between predation number and temperature was fitted by quadratic regression equation. Intraspecific interference was found in the experiment. The average predation number and predation rate of M. sexmaculata decreased with the increasing of its density. The relationship between predation ratio (E) and natural enemy density (P) was described by equation of E=0.9003P^-0.9816. Searching constant (Q) is 0.9003, and disturbing coefficient (m) is 0.9816.

Key words: Menochilus sexmaculata, Macrosiphoniella sanborni, predation, functional response, intraspecific interference