THE CHARACTERISTICS OF INSECT FAUNA IN NORTHWESTERN YUNNAN PROVINCE
滇西北昆虫区系特点

The present paper deals with the characteristics of insect fauna in northwestern Yunnan province. The insect fauna may be divided into the following natural regions. 1. Nujiang river district. The oriental species make up 47.9 per cent of the total, the palearctic orgion species 31.1 per cent and the endemic species 5.1 per cent. 2. Lancang river district, the element of oriental region species is 38.5 per cent of the total, the palearctic region species 37.1 per cent and the endemic species 8.4%. 3. Jinsha river district, the element of palearctic region predominates over that of oriental region. The oriental species occupy 33.7 per cent of the total, the palearctic region species 34.4% and the endemic species 16.6%. The insect fauna of the northwestern Yunnan region is abundant and strange, because the geomorphology and vegetation of this region are very complicated. The different climates, river system, soil and vegetation on different altitudes of the plateau exert strong influence on the insects in their breeding and multiplication. The insects of the northwestern Yunnan are distinctly distributed into 5 zones by vertical zonation.