Hypolimnas bolina is widely distributed in the tropical Asia. Not a few specimens have been recorded in Japan as one of the migratory butterflies. However, their progeny is unable to survive the winter there, although they may breed temporarily during the favourable summer in some year. The females are much more captured than the males, and are classified into the following four forms, each having its own distributional range which does not overlap each other: 1. Philippine form (subsp. philippensis Butler) - Over 50 specimens are recorded in Japan. 2. Formosan form (subsp. kezia Butler) - Over 50 specimens including butterflies produced from some immigrants are recorded in Japan. 3. Red spotted form (subsp. bolina Linnaeus or patauensis Fruhstorfer)- Over 20 specimens have been recorded in Japan since 1957. 4. Continental form (subsp. incommoda Butler) - Only 5 specimens are recorded in Japan. It was noteworthy that three forms, Philippine, Formosan and Continental, were collected together during such a short period as 18 days from Aug. 24 to Sept. 10, 1966, in Miyazaki, southeastern part of Kydshd. An investigation on the air-currents in the year 1966 suggests that the butterflies in question were conveyed up by the Typhoon 12 in the South-China Sea and successively transported into the Typhoon 15 which landed at Miyazaki-city on August 23, 1966. The present account is given on the rearing records of the offspring from the females captured in Miyazaki at that time, with the results summarized as follows: 1. Eggs obtained from Formosan form (e. g. No. A in Table 2) were hatched in a very high percentage and were produced the offspring with 1: 1 ratio of males to females which have the same maternal phenotype. Similar results are also obtained on Formosan form collected at the other place in Japan (unpublished). Some females, however, (e. g. No. C in Table 2) exceptionally produced F_1 offspring whose phenotype varied from intermediate between Formosan and Philippine forms to Formosan one. 2. The hatchabilities of larvae from 4 broods of Philippine form varied from 37 to 100%, while no larvae from other 3 broods of the form hatched at all. Similar data are also known on Philippine form collected in Japan. Although there is no detailed information, it is assumed that sterility of the eggs is due to scarcity of the males in the Philippines, the exodus site of the form concerned. 3. The offspring produced from 3 females of Philippine form were exclusively females closely resembling their mothers. The remaining one brood, however, produced offspring whose phenotype varied from Philippine to Formosan form, including intermediate of them; the parental mating occurred possibly between ♀ Philippine form and ♂ Formosan one at the place where they reached. 4. In Miyazaki-city, a few eggs were found on the leaves of sweet potato, Ipomoea edulis, in the field, but no F_1 butterflies developed in situ at all.
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