MIGRATION AND DISPERSAL OF INSECTS : LEPIDOPTERA. 235 



on the Mexican- Texan frontier of the Rio Grande ; he had only met with 

 one example of inariitK, very much battered and worn, on the Guade- 

 loupe. Friedrich asserts that the hosts of lepidoptera return along the 

 same route five or six weeks later, but in greatly reduced numbers, the 

 survivors greatly exhausted, and the females without eggs. In the 

 table (lor. cit., p. 108) the direction of flight of those observed by 

 Verhuell is given as from south-east to north-west, and of those observed 

 by Friedrich from north to south. Urania Irilns is again noticed in 

 T/ie Awcrican Xatiiralist, in 1872 (referred to Entom., vi., p. 332) as 

 migrating in immense numbers, flying in swarms across the Isthmus 

 of Panama, and equally abundant at Para, Pernambuco and Rio 

 •Janeiro : "From an early hour in the morning until nearly dark these 

 insects passed along the shore in amazing numbers, but most 

 numeroiisly in the evening. It was very seldom that one was seen 

 travelling in the opposite direction." One of the latest records of the 

 migration of one of these beautiful Uraniids comes from Colon, in the 

 Republic of Columbia, where, in March, 1889, Vrania hnisdnralii was 

 observed by Davis, who states {Instrt Life, ii., p. 22) that when within 

 a few miles of Colon, the insects were seen flying from the mainland in a 

 northerly direction across the bay. This migration continued daily 

 from the date of the observer's arrival (March 18th) for nearly a week. 

 When the flight began could not be ascertained. Its duration daily 

 was from just before sunrise until sunset ; it was protracted, however, 

 until late at night on three evenings near and at full of the moon. The 

 point which attracted most attention was the vast number of the 

 insects. " The air was actually full of them. It resembled an unre- 

 mitting shower of forest leaves in autumn." rraiiia fnli/i'iis, however, 

 is perhaps even more remarkable for its migratory habits. It is 

 described by Kirby as migrating in vast flocks, flying at a great height 

 by day, from north to south, or from east to west. 



Mann, writing (/'.s(/r//r, v., p. l(iH) of an observation made in 

 Brazil, in 1871, says that "great numbers of the Vanessid butterfly 

 Coea {Aiianist/ion) acherouta, followed each other singly at intervals 

 across the meadow in front of the house, apparently migrating, and 

 were difficult to catch. They came with powerful, rapid, direct flight, 

 perhaps from three to five metres above the level of the meadow, from 

 the direction of a rising ground or small hill near by. After seeing 

 several and noticing the uniformity of their behaviour, 1 ascended the 

 hill, and thus, so far as I recollect came within reach of them. From 

 how great a distance they came I could not tell, nor can I now say 

 from or to what direction of the compass they Hew. The season was 

 early fall (February 17th, 1871)." We have previously recorded the 

 occurrence of KiKjonia j-albimi in vast swarms, at the Hankaty Head 

 lighthouse on Nantucket Island, and we have already noticed the 

 migrations of I'l/iamcis ranliii, and the fact that Hnraitcssa antiopa has 

 been observed at sea, many miles from tlie nearest land. Another 

 American species, Kni/nnia califoniira, closely allied to these, is also 

 reported as a migrant. Dr. Behr writes (Prac. <'al. Acad. Nat. Set., 

 iii., p. 124) of this species : " The first migration I observed was on 

 November 15th, 185G, when numbers of this butterfly flew over San 

 Francisco in a general direction of south-south-east. They flew singly 

 and never crowded into swarms. Most of these butterflies passed over 

 our streets at too great a height to permit close inspection — a few 



