all 
XXVI1 
Sept. 19-Oct. 12, 1918, after an unusually dry spell, in the 
middle of the wet season, and the speed was at the unusual 
rate of 17 miles an hour. In this migration Mr. Williams 
concludes that the wind, although contributory, cannot have 
been the conclusive factor in determining the direction of 
flight. His maps on Plates VI and X suggest that the mountain 
ranges and the southern coast-line exerted an important 
influence. The following interesting observation on Sept. 27 
proves that migrating individuals are influenced by the flight 
of others, and also proves that this influence does not help us 
to understand how the line of migration is determined. Mr, 
Williams, in attempting to catch examples, noticed that 
‘any butterfly narrowly missed was put off its direction by 
the excitement and flew off wildly in any direction. Other 
butterflies close at hand meeting this butterfly flying out of 
the general order would in turn become confused and some- 
times follow it in its new direction. So that after several 
misses in succession I was surrounded by a number of butter- 
flies flying in all directions. If I stopped attempting to 
catch specimens these would gradually pass away, and the 
regular direction of flight would be resumed” (p. 85). 
Migration of Catopsilia pyranthe, C. crocale, and other 
Butterflies in Ceylon.—Col. N. Manders in Trans. Ent. Soc., 
1904, p. 701, gave an account of butterfly migration in that 
island. The map on Pl. XXXV, together with his description, 
seems to prove that the wind cannot determine the direction, 
being with the stream on its southward course along the 
E. and §8.E. coasts, but strongly against it on the W. when 
the butterflies have turned northward. In Ceylon the 
route clearly seems to be determined by a preference for the 
coast-line and for roads cleared through dense forest (p. 705). 
Migration, apparently in the same direction, occurs in February, 
in the dry season, and in November and December, in the 
wet. This peculiar sequence of migratory waves in the same 
direction is probably to be explained by the fact that females 
are laying their eggs all along the route. ‘‘ Every female 
seemed possessed with the one insane idea of getting rid of 
her eggs with the utmost expedition . . . and then madly 
continuing her flight” (¢bid,, p, 704). 
