RHOPALOCERA NIHONICA. 



Order LEPIDOPTERA. 

 Sub-order RHOPALOCERA. 



The order Lepidoptera is divided into two sub-orders, Rhopalocera and Heterocera. The former 

 includes all the butterflies and the latter all the moths. Butterflies can be roughly distinguished from 

 moths by the following points : They are almost without exception day flyers, and always have more or 

 less clubbed antennae. Moths fly day and night, and generally have simple or pectinated antennas. This 

 is not, however, an invariable rule, as we have many families of moths with antennas thickened towards 

 the point. 



This book treats of the butterflies only, and is the result of sixteen years' constant attention to the 

 group in every part of these islands. 



The butterflies of Japan are a particularly interesting study, not alone to the Entomologist, but also 

 to the general student. We have in this country direct evidence of the transmutation of species, many 

 Japanese butterflies appearing under perfectly distinct alternate forms at different times of the year; these 

 forms of the same insect are often more distinct than undoubted species of the same family. 1 have 

 proved, by breeding, that this multiplicity of form is caused by temperature affecting the insect during 

 its larval stage, and I have produced them artificially. I have styled them temperature forms. The reason 

 of these strange temperature forms appearing naturally, in Japan, is primarily owing to the exceptional 

 amount of change in climate which takes place during the year, and also to the geographical position and con- 

 formation of this country. It is, and has been for long ages, a veritable battlefield in the struggle for exist- 

 ence for the species inhabiting it. At a not very remote period, geologically considered, these islands 

 appeared above the waves as a chain of high mountain peaks, relics of an ancient continent, similar in 

 appearance to what we see the Kurile Islands now are on the map ; the spaces between these old peaks 

 have been filled in principally by recent volcanic agency. 



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