54 REPORT UNITED STATES ENTOMOLOGICAL COMMISSION. 
Ringger, 14 * in the month of October, 1820, observed for the first time 
in Paraguay a swarm of locusts which came over from the right coast of 
Paraguay. This was a species of Acridium. According to Molina, 14 * 
Chili is much less infested with grasshoppers than Cujo and many other 
countries in America. Kefferstein quotes this writer incorrectly as say- 
ing they also show themselves here. According to Fannin, 114 they appear 
to be rare in this country. 
Speaking of Uruguay, Fannin says these pests appear at intervals of 
five, six, or seven years, coming from the north in armies and deposit- 
ing their eggs here. 
Peter Schmidtmeyer observed them in May in immense numbers be- 
tween San Luis and Mendoza. 144 
Darwin's account of the swarm he observed at Luxan, in March, 1825 r 
has already been given in our First Report. 146 We need only to call 
attention to the fact thai they came from the South and in mass, pre- 
senting a cloud of dark reddish-brown color. He erroneously supposed 
them to be identical with P. migratorius, as the species which is migra- 
tory in this part of South America, as has been ascertained by Bur- 
meister, is Acridium paranense. A list of worts relating to the history 
and migrations of this species will be found in our former Report (Ap- 
pendix, p. 278). The Gilliss expedition observed them near San Luis j 
Padre Ovalle, between Mendoza and Buenos Ayres. 1,r 
For accounts of their migrations and operations in Central America 
and Mexico the reader is referred to our First Report. 
REMARKS. 
Having now taken a general but brief survey of the movements and 
operations of locusts in the various parts of the world, we desire, before 
entering upon the discussion of the various topics relating to migration, 
to call attention to certain facts which appear to be indicated by this 
survey. 
The first is, that all the grand divisions of the earth and most of the 
larger faunal regions are more or less subject to ravages of locusts ; but 
that the area of their most abundant development is to be found in North- 
ern Africa, Western Asia, and Southern Europe, or in other words a vast 
semi-circular sweep around the eastern extremity of the Mediterranean 
Sea, reaching from Poland around the Caspian and southern end of Ara- 
bia to Senegal. 
The second important conclusion to be drawn is that wherever they 
are largely and frequently developed, we find either extensive deserts 
142 Rei8e nach Paraguay, p. 420. — Kefferstein. 
» 3 Geog., Nat., and Civil Hist. Chili, Transl., I, p. 146. 
>« "Chili, Paraguay, Uruguay, and Buenos Ayres," In L'Univers, XXV, p. 6. 
i4i "Travels in Chili over the Andes in the years 1820 and 1821," p. 107. 
» 6 P. 466. 
"'First Report TJ. S. Entomological Commission, p. 4G6. The date of the publication of Ovalle'a his- 
tory of Chili as given in our report — 1846— is probably a typographical error, it should be 1646. 
