March, I9I2.] LeNG : C1CINDELID.E IN EASTERN NORTH AMERICA. 11 



either that the northern forms originated long ago from the South 

 American and became entirely separated from them during or prior 

 to the Tertiary period, or would suggest that the long-legged South 

 American forms and their North American relatives actually consti- 

 tute a separate genus of dififerent origin and with other characters 

 (as in the mandibles and elytra) to dififerentiate it from the true 

 Cicindela of the old world with which our northern species are for 

 the most part related. Such a division of the genus has in fact been 

 made though not at present generally adopted. The distribution of 

 Cicindela, thus restricted, would then be in harmony with that of 

 many other genera of Carabidse, the family of which the Cicindelidse 

 are now considered a subfamily. 



Recapitulation. — I have now sketched and illustrated what I con- 

 ceive to be the principal factors controlling distribution of Cicin- 

 delidae on the Atlantic Coast, viz. : 



Temperature as indicated by Merriam's zones, 



Barriers as indicated by Leconte's districts, 



Enviromncnt, etc., as brought out by Criddle, Shelford and others 

 and including the behavior and adaptability of the species. 



Accidents of wind, tide and geological changes, and 



Original Habitat of the species. I propose below to examine the 

 distribution of each species as given in Mr. Harris's Catalogue to see 

 if the factors named are sufficient to account for the ascertained local- 

 ities, dividing the species into three groups, viz., those assumed to be 

 of circumpolar origin, those assumed to be long established in the 

 United States, though originally derived from the same stock as the 

 species of the first group, and those assumed to be of southern 

 origin, mainly the long-legged species. 



Species of Circumpolar Origin. 

 C. longilahris, including the varieties laurcnti, oslari, nioiitaua, 

 vestalia, perviridis, is strongly differentiated by the form of the 

 labrum, a character it shares with the Siberian silvatica, which it also 

 resembles in other respects. It inhabits the boreal zone from ocean 

 to ocean, reaching 58° N. Lat. in British Columbia and on the Atlantic 

 coast is found in Newfoundland, Nova Scotia, Maine, in the White 

 Mts. and in the Adirondacks. It possesses great vitality and capacity 

 for variation but seems quite unable to accommodate itself to the 



