INSECTS IN GENERAL. 89 



soils. The pimelia bipunctata has been observed to move to 

 no great distance from the sea-coast. They are numerous 

 near Marseilles, where M. Latreille made this observation. 

 Other species of the same genus are found in the interior 

 of some countries, such as Barbary, Syria, and Egypt ; 

 but in places where the soil is impregnated with saline par- 

 ticles, or abounds in plants of the genus salsola. Thus 

 they always inhabit localities similar to that of the first- 

 mentioned species. The insects of those countries which 

 border on the Mediterranean, the Caspian, and the Black 

 Seas, exhibit very great inter-relations, and remain for the 

 most part on the ground, or on plants of no great height. 

 Those countries seem to be the chief habitat of certain coleop- 

 tera : and though the Cape of Good Hope is so far distant 

 from them, many of its insects exhibit family traits with 

 the others. These facts prove that many characters of affi- 

 nity exist between the soils and vegetable productions of 

 those widely distant regions. 



The entire, or nearly so, of arachnida and insects which 

 inhabit countries whose temperature and soil are the same, 

 but which are widely distant, is composed in general of 

 different species, and this even when those countries are 

 under the same parallel of latitude. All the insects and arach- 

 nida brought from the most eastern parts of Asia, such as 

 China, are distinct from those of Europe and Africa, what- 

 ever may be the latitudes and temperatures of those Asiatic 

 countries. The majority of these same animals also differ 

 specifically when the countries which they inhabit, identical 

 in soil and temperature, are separated from each other (the 

 difference of latitude making no difference) by natural 

 barriers, interrupting the communication of these animals, or 

 rendering it very difficult, such as seas, very high mountain- 

 chains, or vast deserts. Thus we find that the arachnida 

 and insects, and even many other animals, of America and 



