Linn. 



Although a group of great aiitic|iiity, some of its divisions (especially 

 the cockroaches) being abundant in Paleozoic as in Mesozoic rocks, this 

 order of insects is feebly represented in Tertiarv times. Part of our lack 

 of familiarity with the relics of those clays is due to their rare occurrence in 

 amber, a fact largely due to their generally weak and brief flight. Indeed, 

 hardly a dozen species of the entire order are known or indicated from this 

 source, and less than forty species, including all'mere references as distinct 

 forms, from the European rocks. This number is nearly equaled by the 

 American species described in this volume, but this fact is largely due to 

 the great preponderance of Forficulariuj, which comprise more than a third 

 of the species. The numbers in the different groups are, perhaps, too 

 small to render a particular comparison useful, but we may note that the 

 European rocks have representatives of each family excepting the Phas- 

 mida, while the American furnish specimens of all but the Mantides. No 

 Acridii have been found in amber, and of Locustari;e only larvse; Forficu- 

 lariaj and Mantidse are said by older authors to have been found in amber, 

 but none are now known, the undoubted amber remains being conlined to 

 Blattarue, Phasmida, Locustarise (larva-), and Grryllides. 



In comparing the European and American Tertiary orthopteran 

 faunas some interesting points may be noted. The resemblance of both 

 faunas in a nearly equal degree to warm temperate or subtropical types is 

 a little curious, combined as it is with a distinct differentiation of char- 



; for even where the same subfamilies are represented, as they gener- 

 allv arc, the genera of the two continents are widely different. In the few 

 cases where >perit.-s have been placed under the same generic heading it 

 has usuallv been by the use of the genus in the broad sense, indicating 

 merely sul it'ainil v allii'ities, and the species themselves are widely different 

 The ivM-iiibl.mrr briween the two countries is perhaps most marked in the 



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