CarPENTER—The Geographical Distribution of Dragonflies. 461 
Indies we find but one or two species of the widespread American 
genus Heterina. The Agrionine are considered to be among the 
most primitive of dragonflies, and all the fossil insects referable 
to the sub-family come from the Solenhofen lithographic stone, 
and thus carry us back to the Jurassic period. It is, therefore, 
exceedingly strange that they should be unrepresented at the 
present day in the Australian Region, Madagascar, and the West 
Indies, except by species which are evidently comparatively recent 
immigrants from the neighbouring great continents. For it is 
well known that these countries are specially characterised as the 
sanctuaries of primitive forms of life. Yet it seems probable 
that the Agrionine dragonflies, for some reason, have only lately 
extended their range into these districts. 
The genera peculiar to the Neotropical Region and their allies 
in the Oriental and Ethiopian appear to be the descendants of a 
primitive stock once widespread, for there are three Solenhofen 
species referred to Pseudophea. Then a newer stock seems to be 
represented by the genera at the head of the table—Agrion and 
its allies. These are mostly Holarctic and Oriental, and it is 
remarkable how many genera are represented at the confines of 
the two regions, suggesting that from the Manchurian district the 
insects spread westward to Europe and Africa, and eastward into 
North America. The last genus in the table, Pa/eophiebia, con- 
fined to Japan, is of special interest as the most primitive of 
living dragonfiies, combining the body of a Gomphine with the 
wings of an Agrionine.' 
1D. Sharp: The Cambridge Natural History, vol. v. (p. 427). London: 1895. 
