HEMIPTERA— HETEROPTEEA. 341 



The principal change which may be noted here is the almost total 

 extinction of the Capsidte in the European representation which shows but 

 a single species ; the Saldida; and Hydrobatidaj do not appear and the 

 Aradidse are notably reduced. The greatest contrasts between the Euro- 

 pean and American rocks, with an almost equal total number of species,' is 

 seen in the Capsidse, which have 8 per cent of the total fauna in America, 

 0.6 per cent in Europe, and the Coreidre with 22 per cent in America and 

 11 per cent in Europe ; these are the only cases of sti'iking contrast in 

 wliich the American fauna is the richer; the others are the Reduviida^, 1.3 

 per cent for America, 7.4 per cent for Europe; the Nabidas, none for America, 

 3 per cent for Europe; and the Physapodes 2 per cent for America, 11 per 

 cent for Europe. The contrasted balance of the Lygajidse and Pentatomidse 

 is well seen, America having 33 per cent of Lyg^eidse and 24 per cent of 

 Pentatomidse, Europe 23 per cent of the former and 31 per cent of the latter. 



Very little change appears in the smaller families (a relatively small 

 number of which occur in amber) except in the entire absence of any repre- 

 sentatives of Hydrobatidge and Saldida;, the former occurring in America. 

 It is also surprising to see how little the larger families (with a single excep- 

 tion) are affected by the new table, amber having but the meagerest possi- 

 ble contribution to offer to the Pentatomidse, Coreidse, Lygseidae, and 

 Physapodes, while the single exception noted above of the Capsidse is a 

 startling one, amber furnishing nineteen of the twenty European Tertiary 

 species. 



It may be worth while to extend some of these comparisons in a diflfer- 

 ent direction, that of existing American faunas. There are, I believe, but 

 three opportunities for such comparison. First, Mr. Uhler's Check-list of the 

 North American Heteroptera (188G), wliich embraces all species known at 

 the time, including the Mexican and West Indian ; second, the same writer's 

 valuable List of the Hemiptera of the region west of the Mississippi (1876), 

 wliich represents particularly the geographical region of our Tertiary fossil 

 Heteroptera ; and, third, Mr. Distant's contribution to the Biologia Centi'ali 

 Americana (1880-89), which has a decidedly more southern aspect than 

 Uhler's general list. Distant's work has progressed only through the larger 

 families (in reverse order to that followed here) and indeed at this writing the 

 supplement to the first volume is not complete, and accordingly in what 



' In the euuuieration of the Europeaa specie.s a considerable number of nndescribed species are intro- 

 duced whoso presence has been merely indicated by statements qI' different naturalists. 



