﻿2 毘蟲ゅ；!?(11：^ 第^ 卷 第ぐ ミ號 



MATERIAL.. 



Yüthima philomera var. argUS is a small butterfly belonging to 

 the Subfamily Satyrin お. The variableness of the eye-spots of this 

 variety appears to have attracted attention of many lepidopterologists, 

 for instance, Leech^®^ and Seitz. ひ s) The abundance of individuals is 

 another advantage for the study of variation of the eye-spots : perhaps, 

 no other species of this subfamily are collected with so much easiness as 

 this in the mild district of Japan. All the material, upon which thi^ 

 report is based, was captured by myself ； each lot was collected within 

 an area not exceeding two miles in diameter and under tolerably uniform 

 local conditions. In the mild districts of Japan, this butterfly begins to 

 emerge towards the end of April and continues to be seen during the 

 next month. Then it disappears completely until the end of June. Then 

 the new generation begins to fly about. During summer months the 

 butterfly is very common, especially in the neighbourhoods oi low bam- 

 boo bushes, where the larvae usually find their feeding places. But 

 towards the middle of September, the number gradually diminishes; and 

 in the next month, only a few individuals with worn-out wings are some- 

 times seen. Accordingly we are quite sure that, Lots I, V and X of 

 Table I consist exclusively of the individuals of the spring generation, 

 while the others are all made up of those of the subsequent generations. 



THE LOCATIONS OF THE EYE-SPOTS. 



The eye-spots, on the wings of this butterfly are all apparently of the 

 same nature. The following laws appear to govern their mode of forma" 

 tion:- 、aj the center, or the pupil, falls always upon the crease which 

 passes through the middle line of the interspaces between the Icui ゾ i' し u- 

 dinal nervues : it two pupils, either of one bipupiled spot or of two uni- 

 pupiled, are present in one and the same interspace, there are unexcep- 

 tionally two creases in that interspace, one pupil lying on each : (b) in 

 case the spots occur on both surfaces of the wing, the centers coincide 

 with each other: (c) no spots are formed on the upper surface before the 

 under surface of the same interspace has come to possess them. The 

 above-stated laws seem to be applicable to not only this sptcics but also 



. " い 2) い 0〕 



Other members of this subfamily. The opinions of the previous authors 



