MIGRATION AND DISPERSAL OF INSECTS: LEPIDOPTERA. 155 
which floated on the surface of the water, and, for days afterwards, 
they were to be seen drifting into the various bays in the island of 
Corfu.” It was assumed, as they appeared to be taking the direction 
of the coast of Italy, that they would, in all probability, strike the land 
in the vicinity of Otranto. 
Scigliana observed a great flight at Trapani in 1837; these flew in 
a direction from south to north. Lyell, Coni, Raconi, Ghiliana, Mina- 
Palumbo, and other Italian lepidopterists have recorded similar 
immigrations. In 1878, Failla-Tedaldi first observed one of these 
flights, but during April, 1878, this entomologist witnessed a tremendous 
immigration of this species into Sicily. It commenced on the 26th, 
was renewed on the 28th, and went on until May 8th. The insects 
proceeded in serried columns, formed of ‘‘milliers”’ of specimens; each 
column had a front of four kilométres or more; in Cantelbuono, where 
the streets barred their way they ascended vertically, retook their 
normal direction, which appeared to be directed from the north to the 
south ; the flight was observed in the neighbouring districts. During 
this time, the Scolymus and other plants in flower were covered with 
hundreds of butterflies, and some days afterwards the larve were 
obtained in numbers on several different species of plants. The 
observer notes that the greater part of the specimens observed were, 
worn, faded, and broken on the edges, and some of the examples were 
extremely small ; the latter showed that the insects had been badly placed 
(owing to their great numbers) for food, and the want of proper food- 
plants on which to lay their eggs is suggested by Failla-Tedaldi as the 
cause of their migration. The spring irruption was followed by an 
immense number of newly emerged examples in July, evidently 
descendants of the immigrants. 
The year 1879, will, however, long be remembered as that in which 
one of the greatest and most general migrations of this species occurred. 
A yast multitude of individuals moved from south to north over all the 
countries of south-western, western and central Europe, and as the 
main facts were collected at the time, a very fair general knowledge of 
the extent of the migration and the area affected was obtained. The 
swarm almost certainly came from north-west Africa, was observed at 
Algiers as early as April 15th-20th, travelling in a north-easterly 
direction. From April 26th-30th, Crewe observed countless numbers 
of the butterfly in the neighbourhood of Valencia and Barcelona, as 
well as in Minorca, from May 1st-3rd. Towards the end of May, the 
main part of the swarm appears to have crossed into France, distributing 
itself over the south-eastern districts of Switzerland and north Italy, 
and, on the morning of June 5th, thousands of living speciniens were 
found on the snow at the hospice of St. Gothard. It then spread over 
Germany and Austria, being recorded from various localities from June 
7th-16th. Another column appears to have crossed the Mediterranean 
to Sicily, and spread itself over Italy during June. The more westerly 
end of the swarm reached Strasburg as early as June 3rd-9th, Bisheim, 
June 8th, Angers and Rennes, on June 10th, arriving on our southern 
coasts about June 10th-13th, and spreading hence all over the country 
into Scotland, whilst Belgium and the country directly north were also 
inundated. There seems to have been many branch columns, although 
the greatest possibly was that which passed along the Rhine valley, 
where the lary later destroyed the crops of artichokes and Artemisia. 
