1888.] 2GI 



White Butterflies in Japan. — My September number of the Magazine is just to 

 hand, conveying the intelligence of great swarms of " Whites " in England last year. 

 Now the PieridcB are great fayourites of mine, and I ara always on the look out for 

 anything concerning this group, and have therefore read with much interest all that 

 has been written upon this " inundation," and will give a few notes of my own. 



1886 was the great " White " year in Japan. Pieris napi was very abundant, 

 but Pieris rapcB swarmed. I first noticed great quantities of the latter while 

 travelling from Yokohama to Tokyo early in May. All along the line are fields of 

 rape and radish, which were swarming with Pieris rapes, the train disturbing those 

 on the embankments until we seemed to be accompanied from station to station by 

 a little fluttering white cloud. Shortly after this I left Yokohama for the Ryukyu 

 Islands, and next had my attention attracted by the "White" in the Bay of 

 Kagoshima. This was my first visit to Satsuma, and I was therefore on deck before 

 sunrise, anxious to see this most beautiful Bay. As the sun gained power I first 

 noticed solitary specimens of Pieris rapcB slowly drifting down the Bay in a southerly 

 direction ; as the morning advanced there were hundreds all going to the same 

 quarter before a light breeze which barely ruffled the surface of the water. I had 

 plenty of time for observation, as when we reached Kagoshima before noon, the Port 

 Ofiicials politely but firmly insisted upon our remaining in quarantine for twenty- 

 four hours, and all that day, until between 3 and 4 p.m., when they ceased, the flight 

 was going on. The only other butterfly seen was a fine specimen of Papilio Machaon, 

 which flew about the steamer until captured. After leaving the Bay the next day 

 not a single " White " was to be seen. There were none on Amami Ohoshima where 

 I landed, nor on Okinawa where I collected for three days. I left my collector on 

 that Island, and he remained for some months, with orders to take everything ; 

 among the specimens (some thousands) there was not a single specimen of a 

 White ! 



Now, notwithstanding that I saw the " Whites " apparently " migrating " in 

 the most approved fashion, in thousands, I do not for a moment suppose that the 

 " migration theory " accounts for the superabundant appearance of this or any other 

 species, either in Japan or England. In the first place, there is no evidence or 

 reason to suppose that the swarms seen at Yokohama and Eagoshima had migrated 

 there from anywhere else ; and secondly, it is quite incredible that had the swarm 

 seen at Kagoshima been capable of migrating even in a limited acceptation of the 

 term, that not a single specimen should have been seen on the adjacent Ryukyu. 



I believe that Mr. Jenner's remarks (Ent. Mo. Mag , xxiv, p. 113) sum up the 

 whole mystery. Butterflies multiply so rapidly, that the produce of a few pairs 

 exceptionally favoured by circumstances is sufficient to account for the wholesale 

 appearance of any species either the same season or the next. I have had a very 

 good instance of this during the past autumn and early winter. We have in Japan 

 eleven species of Vanessidce, ten of these are abundant, one (Vanessa cardui) is 

 scarce, and until this year I had only a few specimens, taken singly, at various 

 localities ; but this season it was abundant for the first time during seventeen years, 

 and I could have taken hundreds. This season has been extraordinarily mild, re- 

 sulting in an extra brood, hence its abundance. — II. Peteb, Yokohama : January 

 IQth, 1888. 



