LIXNEAN SOCIETY OF LOXDOX. 27 



i1. has found its historian in Commander J. J. Walker*, who has 

 recorded its westward migration from 1840 (New Zealand) to 1889 

 (Straits of Malacca), and eastward from 1863 (Azores) to 1897 

 (Grecian Archipelago). In many of the localities it has estab- 

 lished itself for numbers of years and appears to be now a 

 permanent i-esident. In spite of all the varying local influences 

 to which it has been subject in its numerous scattered colonies, 

 Commander A¥alker has never seen a record of any form except 

 the North American one. 



It is unnecessary however to rely solely on experiments made, 

 partly by man who has accidentally transported si)ecies to distant 

 lands, partly by nature which has then subjected them to all the 

 strange conditions of the new home. We can appeal to instances 

 in which the whole process has been natural — to local races 

 distinguished by small differences. If now these races, bred in a 

 sti-ange locality, preserve their original differences, the desired 

 test is forthcoming. 



T. Direct Evidence or Hereditary Transmission or Local 

 Difference. 



a. Locrd European and British Itaces of ilie Butterfly Pieris napi 

 hred in the London District. — This butterfly, the common English 

 " Green-veined White," has been long known to form local races 

 in various parts of its range. Many of these have been described 

 and named in works on Eui-opean butterflies. The differences are 

 mainly exhibited by the females but are sometimes fairly well- 

 marked in the males as well. This species has been extensively 

 bred from the egg or from very young larvaj which hatched in 

 transit, by Mr. Hugh Main and the late Mr. Albert Harrison. 

 All the broods were reared at youth Woodford, N.E. Mr. Main 

 has kindly drawn up a brief account of the work : — 



" Being interested in the local forms, etc., of Pieris napi, the 

 late Mr. Albert Harrison and I reared large numbers of this 



* Coiiniiander Walker's papers and notes on this species have all appeared 

 in The Entomologiais Mcmtldij Magazine, and are as follows : — 



(1) " Anosia plexippiis, L. {Banais archijrpus, F.) : A Study in Geographical 



Distribution." (1886, xxii. 217-224.) 



(2) " Anosia ■plexijypus, L. (JJanais archijqms, F.) at Gibraltar." (1886, xxiii. 



162.) 



(3) Observations on the occurrence of " Bajiais pie.vippus" at Dainnia, 



Amboyna, and Ternate. (1893. xxix. 25, 27, 30.) 



(4) Observations on occurrence of '^ Anotiia j^ic^WP'^'^" i" ^^w Caledonia, 



the New Hebrides and the Loyalty Islands. (1902, xxxviii. 192 ct seqq.) 

 (.3) Observations on occurrence of "■ Anosia plexipinis" at Sydney, N.S.W. 

 (1905, xli. 220.) 



(6) "The Geographical Distribution of Danaida plc.vippns, L. (Banais 



archipiyus. F.) with especial i-eference to its recent migrations." (1914, 

 1. 181-193, 224-237.) 



(7) " Some more British records of Danaida plcxippus." (1914, 1. 290.) 



(5) " A note on the distribution of Danaida plcxippits in Australia." (191(>, 



li. 294.) 

 For a brief abstract of the results see Bcdroc/i\ Apr. 1914, pp. 41, 42. 



