Abstract: The reproductive system of Quadrastichu erythrinae Kim adults was studied anatomically.The insect's oviposition behavior was also observed.The reproductive system consisted of internal reproductive organs and external genitals.The female adult had a pair of ovaries,a pair of lateral oviducts,a median oviduct,a spermatheca and an ovipositor.The male adult had a pair of testes,a pair of vas deferens,a pair of accessory glands,an ejaculatory duct and a penis.On the average,there were 9-13 ovarioles in an ovary and 3-7 ova in an ovariole,thus,a total of 54-182 ova in a pair of ovaries.The oviposition process included 4 steps,i.e.,locating egg laying place,puncturing and probing,egg depositing,and resting and cleaning.