402 A YEAR IN BRAZIL. 



or conical shape is lost under the numerous bosses which have 

 been thrown out in all directions. Professor Drummond has 

 published a very interesting article * on the " Use of the Termite in 

 the Economy of Nature." He argues that they perform in the 

 tropics a similar work to that which is carried out by ^ the earth- 

 worm in the temperate zones. 



DERMAPTERA OR ORTHOPTERA. 



Mr. Francis Walker states, at the end of his catalogue, that the 

 name Dermaptera, given to these insects by De Geer, has the 

 right of priority ; they were afterwards called Orthoptera by 

 Olivier. Respecting their geographical distribution, he says they 

 generally are more limited to warm regions than are the other 

 orders of insects, which also more or less precede them in time 

 of yearly appearance. In regard to the way in which ramifi- 

 cations from the Dermaptera in tropical regions have converged 

 towards the poles, some tribes appear to have left their first 

 habitation entirely as the increasing heat and dryness deprived 

 them of circumstances essential to their existence, and some 

 seem to have increased in numbers and variety after their 

 migration. The advance to the north from the equatorial regions 

 may be included in four principal divisions : first, through China 

 to Japan ; second, from the East Indies along the Himalaya 

 and other mountain-ranges to West Asia and to Europe ; 

 third, from Central Africa to North Africa and Europe ; fourth, 

 from Equatorial America to North America. The regions on 

 the south of the equator from three principal divisions : first, that 

 of South America, where insect life is most abundant ; second, 

 Australia and the numerous neighbouring islands ; third, South 

 Africa, where the insects are least numerous. Mr. Brunner de 

 Wattenwyl, in his essay on the geographical distribution of the 

 Blattariae, has divided the globe into sixteen regions nine of 

 these are north of the equator, two are south, five are on both 

 sides, of which South America towards the Atlantic is one. Mr. 

 Walker gives a list of the special genera of all the Dermaptera 

 found in each of these sixteen regions. 



* Good Wotds, May, 1885. 



