1878. | 471 [LeConte. 
And also these relations with more distant regions: 
Argopistes ; Florida and North Eastern Asia. 
Onota ; Florida and South America. 
Brachypeplus (section); Florida and Africa. 
Mesites ; Florida, Delaware and Europe. 
Stenoscelis ; Southern States and Cape of Good Hope. 

A remarkable feature in the geographical distribution, as exhibited by 
this list of Coleoptera is the comparatively small number of species common 
to Florida and the Antilles. A little reflection on the geological develop- 
ment of Florida, and its relation to the Gulf Stream will show the reason 
for this apparent anomaly. 
The Peninsula of Florida has extended south ward during comparatively 
modern times by the gradual growth of coral reefs and their subsequent 
conversion into land surface; this surface would naturally be occupied by 
the insects and plants living in the conterminous northern regions, as far as 
they were able to endure the approach to a tropical climate. On the other 
hand the Gulf Stream, more and more compressed by the narrowing of the 
strait between Florida and Cuba, would have a tendency to interrupt all 
transfer of living beings from the Island to the Continent; while the 
passage of species from the coast of Mexico and Northern South America 
to either Florida or the Antilles would be slightly facilitated. 
The occurrence of Sosylus and Dacoderus, in the deserts near the Pacific 
coast and in San Domingo must be referred to a much older condition of 
things, when the connections of land surface were quite different from that 
of the present time ; and in fact the characters of the genera indicate that 
they are old forms. Sosylus is a Colydiide related somewhat to the Aus- 
tralian and North American Derataphrus; while Dacoderus differs from 
every other Tenebrionide by the front coxe being contiguous. 

