The spider was collected by the author at Omogokei, Ehime Prefecture, Sikoku, on May 26, 1970. The coloration of the carapace, chelicera and abdomen shows that of a female in the right half, whereas the left half is distinctly that of a male; the right legs are typical for a female, while the left ones are exactly like those in a male. The right chelicera is thick and long as in a female, while the left one is thin and short as in a male. The right palp is slender, and the left palp is well deve-loped, i.e. the right is feminine and the left is masculine. The right legs are slightly shorter than the left ones. The spination on the right legs shows as in a female, and that on the left as in a male. The abdomen is asymmetrical, with the right side being larger than the left. The epigynum shows imperfect condition. The left spinnerets are a little shorter than the right ones.
The present gynandromorphic spider was collected by the author at the Ashiu Experimental Forest of Kyoto University, Miyama-chô, Kitakuwata-gun, Kyoto, on June 15, 1969. In dosal view, the coloration of the carapace and the left half of the abdomen is similar to that of a normal male, but the right half of the clypeus is darker than the left half. The tibiae of both palpi are slightly differentiated. The tarsus of the left palp is merely swollen, and the structure of its genital bulb is not fully developed. The right palp is simple and has a claw at the apex, The spination of all legs is as in a male, and the retrolateral sides of femora of leg I and leg II are dark brown as in a male. The abdomen is asymmetrycal, curved to the left, and the right side has five small spots in a row, while those spots on the left side are connected with each other as a long fleck. The left side of the epigynum is of normal female structure being somewhat incomplete ; the right side does not show such a structure. Considering all facts, this individual seems to show an intersexual mosaic gynandromorph with a preponderence of male elements.
In order to make clear the life history of Pirata subpiraticus, surveys in paddy fields were carried out from 1967 to 1968 at Utsunomiya, Tochigi Pref. The spiders that collected from paddy fields were preserved in 70%, methyl alcohol and the widths of the carapace were measured by means of an ocular mi-crometer (unit=0.05mm). Eggs in egg-sacs held by adult females were counted. P. subpiraticus overwintered under the soil of paddy fields in the immature forms of various stages ranging from hatching larvae to subadults. The instars of these larvae were however impossible to discriminate by the pattern of frequency distribution of the width of the carapace and its length (Fig. 1). The adults formed two peaks of occurrence a year, the first in early July and the second in early August (Fig. 3). In the adult females the carapace widths were over 2.0mm in the majority of the specimens collected before July, whereas those were under 2.0mm in 80% of the specimens collected after August (Fig. 4). On the adult males, the same tendency was recongnized (Fig. 5). From these results it was estimated that the adults emerged before July were of the overwintering generation and those after August were of the next genera. tion (summer generation). Number of eggs was counted for 75 egg-sacs throughout the adult emergence season. An egg-sac had about 50 eggs in average (range 12-105, Table 1). The egg-sacs before July had more eggs than those after August.