Of the remaining orders of insects we know as yet very little. Central Asia and even Siberia are only beginning to be explored, and their invertebrate fauna--except _Lepidoptera_ and _Coleoptera_--is practically unknown. However, I cannot conclude this short summary of some of the more characteristic Alpine animals without referring to the Grasshoppers which are so conspicuous in the mountains. The mountain air simply rings during a bright summer's day with the loud and cheerful song of millions of these insects. It is one of the most vivid impressions a tourist brings back from Switzerland--this constant shrill sound issuing from an apparently invisible source.
Among these Grasshoppers there are some highly characteristic Alpine genera. _Pezotettix_--formerly known as _Podisma_--is one of these. _P. alpinus_ is almost confined to the high Alps; with _P. mendax_ it occurs in lower levels chiefly towards the south-east, that is to say, in the direction of Hungary, Servia, and Dalmatia. _P. frigidus_ occurs not only in the high Alps, but also in Lapland. _P. Schmidti_ and _P. salamandra_ are found in Carinthia, Servia, and Transylvania; and one species also inhabits the Pyrenees and another the Italian Mountains. Finally, the only English species of _Pezotettix_, viz. _P. pedestris_, has been taken in Sweden, Denmark, and then again in Austria, Hungary, Servia, etc., as far east as the Volga, and also on the high Alps, in Sardinia and the Abruzzi Mountains in Italy.
Very little, as I remarked, is known of the Asiatic range of this genus, but either the same or a closely allied one has many representatives in North and South America. Whether _Pezotettix_ is therefore of Asiatic origin we cannot positively affirm, but whatever view we take, the general range of the European species indicates that the migration took place from the Alps in a south-easterly direction, or to them in a north-westerly one. That is to say the Oriental route, and not the Siberian, was utilised by the migrants.
Fortunately, we know a little more about another Grasshopper genus, called _Chrysochraon_. There are only two species, one of which, _Chr. dispar_, has been found from Northern France to the mountains of Servia, but not in the Alps. The other, _Chr. brachypterus_, has a somewhat similar range in the plain; but, moreover, it inhabits the Alps up to a considerable height. It is interesting to note that both these Grasshoppers again turn up on the Amur in Eastern Siberia.