EANGE OF PACHYTYLUS MIGEATOEIUS. 
63 
the middle of France, and A. peregrinum in Algiers. Bolivar, who is 
certainly well informed in reference to the Orthoptera of the Spanish 
peninsula asserts 163 that no data exist authorizing him to affirm the 
presence of this species in the peninsula, but that the citations doubtless 
refer to P. cinerascens. He does not admit P. migratorius in his list- 
For these reasons and others which might be adduced we conclude that 
the starting point of the boundary line should be placed much farther 
east than given by Koppen. Just where, we are unable to decide from 
our data, but it should not include Italy. 
It is a significant fact that the great swarms entering Germany, Poland, 
Hungary, and even Bulgaria, as will be seen by reference to the preced- 
ing quotations, are always from the east, never from the west or south. 
As is evident from the facts presented in the foregoing review, and as 
shown by our observations of the movements of C. spretus, locust-swarms 
almost universally move in direct lines ; hence it is fair to presume that 
the swarms which have swept over Central Europe for the past thousand 
years from the vicinity of the Black Sea to Poland, Germany, and Aus- 
tria had their origin in some productive hive in the East, either around 
or beyond that sea. Nor should we omit the important fact that the 
swarms which can be identified with any reasonable probability as being 
of this species which have visited Italy or France, have proceeded from 
Hungary, or some point in that direction. 
That this species is found in Southern Eussia, and in the countries 
east of the Black Sea to the Irtish and the Chinese border, is a fact well 
known. How far east along this latitude it extends is a question of doubt 
which Koppen fails to remove. That China has been subject to locust 
invasions from time immemorial is shown by the records of that empire, 
but whether this species is the one committing the ravages in that coun- 
try has not, so far as we are aware, been satisfactorily determined. 
That this species should be found in India, we admit, is against the 
theory we are here advancing, yet the evidence to this effect is too strong 
to be disputed. It is somewhat strange that the data in reference to 
the Indian locusts are so meager, when we take into consideration the 
fact that so many scientific explorers have visited that country. 
That A. peregrinum is the chief destructive locust of that section, we 
think is evident from the facts given below, but that P. migratorius is 
also found there, and often in great numbers, must be admitted. The 
most recent authority we have at hand on this point is a series of papers 
issued by the revenue department of the Government of Madras in 1878, 
in reference to the locust visitation of that year, which appears to have 
been very extensive. 
We think it pretty evident that the locusts along this tropical belt are 
chiefly species of Acridium — A. peregrinum — and its varieties, or closely 
allied congeners. The swarms observed by Olivier in Central Arabia, 
Mesopotamia, and Persia, consisted of this species. The Gryllus grega- 
Synopsis Ortop. Esp. y Portug., p. 140. 
