クロゴキブリ幼虫期の雌雄判別

Abstract

The morphological characteristics in the terminal part of abdomen of Periplaneta fuliginosa (Serville) were studied from the newly emerged first instar nymph through the whole developing stages until adults. Except the first instar nymphs which were obtained escaping from the oothecae the specimens used for the present observations were collected by the bait traps set in a building. The morphological changes which took places during the course of developing could be traced into two directions, that is, one to female adult and another to male adult. The presence and the developing of a notch at the middle of hind margin of the ninth abdominal sternite as well as the styli growing on the ninth sternite, and the striking development of the seventh sternite were noticed in the specimens developing to females. With the specimens growing to males no notch was observed at the margin of the ninth sternite and either the eighth, the ninth sternites or the styli remained unreduced while developing. These characteristic features enabled the sexing of cockroach through the whole developing stages.