371 M. Latreille on the Geographical Distribution of Insects. 
bary, in Syria, in Egypt, & c. presents other species of the same 
genus, it is because the soil is there impregnated with saline 
particles, or abounds with plants of the salt-wort kind, Salsosa ; 
thus these pimelise always inhabit an analogous soil. The in- 
sects of the countries which border the Mediterranean, the 
Black, and the Caspian Seas, bear a great relation to each other, 
and for the most part abide on the ground, or on plants little 
elevated. Those countries seem to be the principal seat of the 
second section of Coleoptera (the heteromcres ,) and of the gene- 
ra Liams, B r achy cents, Buprestis , (the conical formed species,) 
&c. ; and although the Cape of Good Hope is so far dis- 
tant, yet many of its insects bear the features of a family re- 
semblance with those just mentioned. From this fact we may 
draw the inference, that the soil and the vegetable productions 
of these different countries possess many characters of a natural 
affinity. 
It is easy to see that the same care should be observed in 
the local observation, as well of the species which live in water, 
of which it is necessary to distinguish the nature, as of those 
which reside along the shores. All such accessory knowledge 
may throw light upon the particular habits of these animals, or 
give rise to reasonable presumptions. Having thus called the 
attention of travelling naturalists, and presented some prelimi 
nary observations, I come directly to my subject. 
The following propositions are established on the study which 
I have made of one of the most beautiful museums of Europe, 
of the private collections of Paris, and on the information which 
I have acquired, as well from published works as by my own 
researches, and a widely extended correspondence. 
1. The whole, or a very great proportion of the Arachnides 
and Insects, which have for their birth-place countries of which 
the temperature and soil are the same, but separated by a great 
space, is composed in general of different species, even though 
such countries may lie under the same parallel. All the Insects 
and Arachnides which have been collected in the most eastern 
parts of Asia, such as China, are distinct from those of Europe 
and Africa, whatever may be the latitude and temperature of 
these Asiatic countries. 
2. The greater number of the above-named classes of ani- 
mals, differ from each other specifically, when the countries in 
