The breeding place of Toxorhynchites aurifluus and relationship of its breeding with climate have been investigated from April to November in 1985 in Shcn-nong-jia Forest Area, Huhci Province, Tx. aurifluus breeds in holes of the (ree Quercus varibilis. The breeding rate is 11.8 %. The larger the tree-hole opening, the bigger the water amount and the darker the water is, the more breeding opportunity Tx. aurifluus has. The amount of ammonia nitrogen and oxygen consumption of water hold in tree-holes breedin...