卵形异绒螨的形态和生活史研究(真螨目：绒螨科)

卵形异绒螨Allothrombium ovatum Zhang et Xin，1992是我国北方地区棉蚜Aphis gossypii Giover，1877的一种外寄生性天敌。通过室内饲养和田间观察结果表明：该螨一年发生一代，以卵在土壤内越冬。在年平均温度13.7℃条件下，其卵、前幼螨、幼螨、若蛹、若螨、成蛹和成螨的发育历期平均为220.8d、19.5d、22.0 d、12.0 d、13.0 d、13.0 d和59.O d。另外，本文还对卵形异绒螨主要虫态的形态和习性进行了描述和研究。

A STUDY ON THE MORPHOLOGY AND LIFE HISTORY OF ALLOTHROMBIUM OVATUM (ACARIFORMES:TROMBIDIIDAE)

Allothrombiurn ovaturn is an ectoparasitic natural enemy of the cotton aphidAphis gossypii in North China. By laboratory rearing and field observations, it was found that this mite has one generation a year in Shanxi Province and overwinters in egg stage in soil. The developmental durations of egg stage, prelarva, larva, nymphochrysalis, nymph, preadult and adult were found to be 220.3, 19.5, 22.0, 12.0, 13.0, 13.0 and 59.0 days respectively at the mean annual temperature 13.7℃. Its seasonal occurrence was recorded in the field in Shanxi Province. The larvae appear in late spring and early summer, and the nymphs and adults emerge in summer and autumn. The morphology and habits of the developmental stages are described.