XVil 
breeze from the 8.E: would begin and last most of the night 
until about 7.30 a.m., when there was no breeze at all, so 
that this period of the day was extremely hot. 
“Tn each case P. cardwi was going against the wind-current. 
The butterflies flew very close to the ground, and they had 
a fairly high bluff (70 ft.) to get up before reaching the culti- 
vated land which sloped gradually away from us to the 
Turkish lines. The period during which the observations 
were made lasted from about April 27 to about May 7.” 
MEDITERRANEAN 
Single arrow-head = direction of morning sea-breeze and of Pyrameis 
cardui against it. 
Double arrow-head = direction of evening land-breeze and of cardui 
against it. 
Zigzag line = bluff with Major Pendlebury’s observation-post, shown 
by circle. 
Thick line crossing bluff and observation-post = observed line of flight 
of cardui. 
Dash-and-cross line = British trenches. 
Dash-and-dot line = Turkish trenches. 
Mr. ©. B. Williams’ record of the migration of Calpodes 
ethlius in Central America agrees with that of Major Pendle- 
bury in the smaller numbers of the return flight in the evening 
(Proc. Ent. Soc., 1919, p. xxiii). It is possible that in both 
instances the streams were gradually dispersing over a favour- 
able country, so that each day only a certain proportion of 
the crowd continued the migration. 
It is, I think, in every way probable that the diurnal back- 
PROC. ENT. SOC. LOND., v, 1921. B 
