CHAP. XV.] THE NEARCTIC REGION. 123 



forms. A considerable number of Xeotropical types enter the 

 southern States ; but there are hardly any peculiar genera, except 

 one of the Lyctenidae and perhaps a few among the Hesperidse. 

 The most conspicuous feature of the region is its fine group of 

 Papilios, belonging to types (P. turnus and P. troilus) which are 

 characteristically Xearctic. It is also as rich as the Palsearctic 

 region in some genera which we are accustomed to consider 

 as pre-eminently European ; such as Argynnis, Mditcca, Gra^yta, 

 Ckionahas, and a few others. Still, we must acknowledge, that 

 if we formed our conclusions from the butterflies alone, we could 

 hardly separate the Xearctic from the Paltearctic region. This 

 identity probably dates from the IMiocene period ; for when our 

 existing arctic regions supported a luxuriant vegetation, liutterflies 

 would have been plentiful ; and as the cold came on, these would 

 move southwards both in America and Europe, and, owing to the 

 long continuance of the generic types of insects, would remain 

 little modified till now. 



Coleoptera. — Only a few indications can be given of the 

 peculiarities of tlie Nearctic coleoptera. In Cicindelidse the 

 region possesses, besides the cosmopolite Cicindela, four other 

 genera, two of which — AmUy chile and Omus — are peculiar to 

 the West Coast and the Eocky Mountains, Of Carabidae it 

 possesses Dicmlus, Pasimachus, Eurytrichus, Sphceroderus, Pina- 

 codera, and a number of smaller genera, altogether peculiar to it ; 

 Hclluomorpha, Galcrita, Callida, and Tctragonodcrus, in common 

 with South America ; and a large number of cliaracteristic 

 European forms. 



The Lucanida? are all of European types. The region is poor 

 in Cetoniida:>, but has representatives of the South American 

 Euplioria, as well as of four European genera. Of Buprestidfe 

 it has the South American Actcnodcs ; a single species of the 

 Ethiopian and Eastern Bdionotc, in California ; and about a 

 dozen other genera of European and wide distribution. 



Among Longicorns it possesses fifty-nine peculiar genera, 

 representatives of five Neotropical, and thirteen Palasarctic genera; 

 as well as many of wider distribution. Prionus is the chief 

 representative of the Prionidse; Leptura and Crossidius of the 



