828 © CHARLES PauL ALEXANDER 
Within the United States the Arctic-Alpine zone is restricted to the area. 
above timber-line on the summits of high mountains.” (Merriam, 
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 transcontinental coniferous forest — a forest of spruces 
and firs stretching from Labrador to Alaska— and . . . Inthe 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 
Carolina.’”’ (Merriam, 1898: 19.) 
The following plants may be considered as Hudsonian species: 
Hierochloé alpina (Sw.) R. & S. Ranunculus lapponicus L. 
Poa laxa Haenke Empetrum mgrum L. 
Scirpus caespitosus L. Rhododendron lapponicum (L.) Wahlenb. 
Carex capillaris L. Cassiope hypnoides (L.) D. Don. 
rariflora Smith Arctostaphylos alpina (L.) Spreng. 
rigida Good. Vaccinium caespitosum Michx. 
capitata L. uliginosum L. 
Juncus trifidus L. Vitis-Idaea L., var. minus Lodd. 
Salix herbacea L. Diapensia lapponica L. 
Uva-ursi Pursh Primula mistassinica Michx. 
Betula glandulosa Michx. Pinguicula vulgaris L. 
Arenaria groenlandica (Retz.) Spreng. Prenanthes nana (Bigel.) Torr. 
Sazifraga aizoides L. Solidago Cutleri Fernald 
The following species of crane-flies may be considered as Arctic-Alpine 
species finding their southern limit in the Hudsonian zone: 
Rhabdomastiz caudata (Lundb.) Tipula centralis Loew 
Tricyphona hannai Alex. labradorica Alex. 
hyperborea (O. S.) loewiana Alex. 
Tipula aperta 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.) 
