著者

木場 一夫

出版者

東京動物學會

雑誌

動物学雑誌

巻号頁・発行日

vol.50, no.2, pp.53-61, 1938

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The present paper deals with Apus sinensis UENO (=A. numidicus var. sinensis UENO) inhabiting a temporary pond in the grounds of the Hoten Shrine in Mukden. The water of the pond was fed by an artesian well in its neighbourhood and was introduced for the first time in the beginning of June, 1937. The greatest depth of the water was about 30 cm on July 1st and the water was yellowish brown in color due to the dissolution of loess-like clay which forms the pond-basin. The temperature of the pond water on the afternoon of July 2nd was as high as 33℃, which nearly corresponds to the air-temperature at that time; the pH-values of the water were 6.6-7.1. This habitat seems therefore to be suitable for the propagation of the species which can endure a considerably higher temperature. Since the supply of water by the pump was stopped on July 22nd, the pond dried up on 24th of the same month. All the inhabitants, including Apus sinensis, Eocyzicus mongolianus, certain aquatic insects and tadpoles, exposed in consequence their dead bodies in air. On july 1st, 2nd and 13th there were collected total 362 individuals of Apus sinensis, 200 of which were measured and closely examined. 1. There is a marked difference in the form of the carapace between both sexes. The carapace is more strongly curved downward on both sides in the female than in the male, and the ratio of its median length to the total length of the body is also greater in the female than in the male. 2. The female is much more dark green in color than the male. 3. The number of somites uncovered by the carpace varies greatly, but it is usually greater in the male than in the female. 4. The number of the post-pedigerous somites is comparatively constant, 8-11 (average 9.4) in the male and 5-7 (average 6.6) in the female. 5. In the male the spinules on the ventral posterior margin of the telson and on the ventral surface of the caudal rami are scale-like in shape. 6. The caudal rami are mostly shorter in the male and longer in the female than the total length of the body. 7. The egg is spherical in shape, reddish brown in color, and is 0.4-0.5mm in diameter. The number of eggs carried in the egg-sac is from 73 to 186 in four females examined. 8. Two hundred and sixteen males were found among 362 individuals caught in the pond mentioned; the ratio of the male to the female is therefore 1.5:1.