Abstract
Abraxas miranda is dormant during the hottest season and more or less active in the cooler seasons. In order to analyse the causal relations involved in this seasonal cycle, the effects of photoperiod and temperature upon the incidence of diapause were studied. It was found (i) that Abraxas miranda responds to photoperiod in the larval stage by three different patterns of developmeht in the pupal stage; (a) that the daylength ranging from 14 to 16 hours or longer induces long diapause which is ecologically associated with aestivation; (b) that the daylength ranging from 11 to 13 hours induces short diapause which occurs before winter; (c) that the daylength ranging from 7 to 9 hours prevents diapause of either type; and (ii) that high temperature acts in concert with long photoperiod, and low temperature does so with a short or medium photoperiod. Based on these relationships, the seasonal cycle of Abraxas miranda is causally interpreted.
The author wishes to thank Professor F. Ohmachi of this laboratory for his constant interest and encouragement during the course of this work. His thanks are also due to Dr. T.O. Browning of the University of Adelaide for revising the manuscript and giving invaluable criticism, and to Mr. H. Inoue of Fujisawa for much useful information on the taxonomic relations in the genus Abraxas.
