_Ryothemis_, another genus of Dragon-flies, has originated perhaps somewhat farther east than the last, for no less than thirteen species are found in Australia, a like number in India, five in Madagascar and Africa, and five in the Holarctic region. Both of these genera are entirely absent from America, and they have possibly travelled to Europe together. Among the European _Orthoptera_--the group to which our Earwigs and Grasshoppers belong--there are also a good many instances of Oriental migrants. One of the most striking of these is the curious "praying insect" (_Mantis religiosa_). It occurs all over Southern Europe, and ranges as far north as the north of France. It is also found in Southern Germany and in Austria, and has a vast extra-European range. There are even records of its occurrence from all parts of Southern Asia and Java and a great part of Africa. That it belongs to an extremely ancient genus is testified by the fact of its presence in Mauritius, Japan, Australia, New Zealand, South America, and Madagascar. The genus _Bacillus_--to which the typical Stick-insects belong--has a somewhat similar geographical distribution. But no less than four species of _Bacillus_ are known from Europe, according to our great authority Mr. Brunner von Wattenwyl--all from the south; and some of these also range into North Africa. There are thirty-two other species distributed over Southern Asia, Africa, Australia, New Zealand, and the Sandwich Islands. Volumes, indeed, might be filled with lists of species and genera of terrestrial invertebrates of Oriental origin, but I will not weary the reader with further enumeration of such instances. Just two more, however, before concluding, as I have not alluded to the large group of the _Arachnida_. Two peculiar spider-like genera, viz., _Galeodes_ and _Rhax_, are found in Southern Europe. Both occur also in North Africa, and in Western and a portion of Southern Asia. As the whole family altogether has an Asiatic character, I cannot agree with Mr. Pocock, who considers them of European origin and believes that they are migrating eastward. But not only terrestrial forms migrated to Europe from Western and Southern Asia. Freshwater species also took part in this great Oriental migration. I need only refer to the freshwater Crab (_Thelphusa fluviatilis_), with which Southern Europeans are familiar. It is the sole representative of a large genus which ranges east as far as Australia and southward to Madagascar and the Cape of Good Hope. The European species is found in Turkey, Cyprus, Greece, Southern Italy, Sicily, North Africa, Southern Spain, Syria, and Persia.