828 Charles Paul Alexander 



Within the United States the Arctic-Alpine zone is restricted to the area 

 above timber-Une on the summits of high mountains." (Mcrriam, 

 1898:18-19.) 



The crane-flies in this zone are considered in connection with those 

 in the Hudsonian zone. 



The Hudsonian zone. — "The Hudsonian zone comprises the northern 

 part of the great ti'anscontinental coniferous forest — - a forest of spruces 

 and firs stretching from Labrador to Alaska - — and ... In the eastern 

 United States the Hudsonian zone is restricted to the cold summits of 

 the highest mountains, where it occurs in the form of a chain of widely 

 separated islands reaching from northern New England to western North 

 Carohna." (Merriam, 1898:19.) 



The following plants may be considered as Hudsonian species: 



Hierochloe alpina (Sw.) R. & S. Ranunculus la-pponicus L. 



Poa laxa Haenke Empetrum nigrum L. 



Scirpus caespitosu^ L. Rhododendron lapponicum (L.) Wahlenb. 



Carex capillaris L. Cassiope hypnoides (L.) D. Don. 



rariflora Smith Arctoslaphylos alpina (L.) Spreng. 



rigida Good. Vaccinium caespitosum Michx. 



capitata L. uliginosum L. 



Juncu^ trifidvs L. Vilis-Idaea L., var. minus Lodd. 



Salix herbacea L. Diapensia lapponica L. 



Uva-ursi Pursh Primula mistassinica Michx. 



Betula glandulosa Michx. Pinguicula vidgaris L. 



Arenaria groenlandica (Retz.) Spreng. Prenanthes nana (Bigel.) Torr. 



Saxifraga aizoides L. Solidago Cutleri Fernald 



The following species of crane-flies may be considered as Arctic-Alpine 

 species finding their southern Umit in the Hudsonian zone: 



Rhahdomastix caudaia (Lundb.) Tipula centralis Loew 



Tricyphona hannai Alex. labradorica Alex. 



hyperborea (O. S.) loeioiana Alex. 



Tipula aperla Alex. piliceps Alex. 



appendiculata Loew septentrionalis Loew 



arctica Curt. serrulata Loew 



balioptera Loew subfasciata Loew 



besselsi O. S. ternaria Loew 

 canadensis Loew 



The Canadian zone. — "The Canadian zone comprises the southern 

 part of the great transcontinental coniferous forest of Canada, the northern 

 parts of Maine, New Hampshire, and Michigan, . . . and the greater 

 part of the high mountains of the United States and Mexico." (Merriam, 

 1898:19.) 



