340 



TERTIARY INSECTS OF NORTH AMERICA. 



Of the other smallex' famiHes the only ones which surpass more than 

 five known fossil species in all are the Nabiclse with seven species and the 

 Tingididse with eight ; of these there have been found in America no Nabi- 

 dee whatever and the smaller lialf of the Tingididaj. Other fixmilies not found 

 in America are the Nepidte, Belostomatidse, Naucoridfe, Saldidse, Limnoba- 

 tidae, and Aradidse, all but the Saldida^ having more than one species in 

 Em'OjDe. On the other hand the only family found in x\inerica and not in 

 Europe is the Acanthiidae with a single species. The remaining smaller 

 famiHes represented on both continents vary in their numbers from one to 

 three in America and from one to four in Europe. 



If, however, we omit from this enumeration tlie forms wliich have been 

 found in amber, and thus compare those of the rocks only, as in the follow- 

 ing table, we shall meet with somewhat different results. 



Table of fossil Beteroptera from rock deposits. 



