DESCRIITIONS OF SPECIES. 



Family RHYNCHITID^E. 



There is no fiiiiiily of Ainoricaii Rhvnfho])hor;i jjaleontolog-ically more 

 interesting' tiian the Kliynchitida'. In point ot" numbers the species of this 

 oniup form 10^ per cent of the fossil Rhynchophora of North America, 

 while the recent species comprise less than 2^ per cent of the existing fauna. 

 They were also vastly more numerous, both absolutely and relatively, than 

 in Kurope, where they compose only about 33 per cent of the Tertiary 

 Rhynchophora. 



In keeping with tliis fnct of tlicir nmnerical importance is that of their 

 variety of type. (Jur existing native species have been grouped in two sub- 

 families, one composed of three genera, the other of one. All these genera, 

 excepting Pterocolus, the type of the Pterocolina;, are recognized among 

 our fossils, l)ut they include a mere fraction of the fossils, which embrace, 

 besides a new generic furiii of Rhynchitina', an entirely new subfauiily of 

 Rhyncliitidty with two tribes, seven genera, and thirteen species, about 

 equally divided between the two tribes. The total number of fossil species in 

 America is therefore fully two-thirds that of the existing forms, a proportion 

 which altogether surpasses that found in any other fainily of insects. Nor 

 is there any other family of fossil insects where it has been found necessary 

 to establish a distinct subfamily grou]) for an entire series of new forms. 

 The abundance and variet}' of Rhynchitida' may therefore be looked ujion 

 as the most striking feature in the Tertiary Rhj'nchophorous fauna of North 

 America. Of the twenty species found in our Tertiaries, three quarters are 

 found exclusively at Florissant. 



Subfamily RHYNCHITINyE. 



Each of the three genera of Rhynchitina- now found in North America 



a))pears to be represented in our Tertiaries, two of them by a single species 



each at Florissant, Fugnamptns by two species at Green river; and liesides 



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