Biology of the Membra cidae oj" the Cayuga Lake Basin 207 



In connection with the discussion of fauna! and floral areas it may be 

 noted that Bray (1915:70-79) lecognizes six plant zones in New York. 

 State, as follows: 



A. Zone of willow oak, sweet gum, persimmon, etc. 



Staten Island, southern Long Island, and narrow belt along northern shore of Long 

 Island Sound. 



B. Zone of oaks, hickories, chestnut, etc. 



IMorainic region of Long Island and Staten Island; Hudson Valley; Delaware, Sus- 

 quehanna, and Alleghany drainage valleys, etc. 



C. Alleghanj'-Transition Forest Zone of sugar maple, beech, yellow birch, etc. 



Alleghany plateau region and Catskill.s below the spruce-balsam zone. Favorable 

 edaphic situations thruout the State up to about 2000 feet. 



D. Canadian-Transition Zone of Zone C species, with a tendency toward dominance of red 



spruce, balsam, and mountain ash. 



Catskills from 2000 to 3700 feet, and Adirondacks up to 3500 feet. 



E. Canadian Zone of red spruce, balsam, and paper birch. 



Highest Catskills, and Adirondacks above 3r)00 feet. 



F. Arctic flora of Adirondack peaks. Zone of far club-moss, alpine holy-grass, mountain 



spear-grass, etc. 



Summit of Mount ]Marcy above 5000 feet; Blount Mclntyre and Whiteface 

 summits. 



KEYS TO C.ENERA AND SPECIES OF THE CAYUGA LAKE BASIN, WITH 

 TECHNICAL DESCRIPTIONS AND LIFE HISTORIES 



The following review attempts to estal)lish the taxonomic position of 

 each genus and species, and includes for each form a short iMbliography. 

 a technical description, and the more important facts regarding life 

 history, local distribution, and relative abundance. 



In the systematic discussion the genera and the species are located by 

 means of keys and descriptions so that they may be easily distinguished. 

 The dichotomous tables used are admittedly artificial in many respects, 

 but it is believed that with the limited number of forms involved they will 

 prove satisfactory. In all cases, of course, the function of such keys is 

 to direct rather than to establish, and the description, rather than the 

 key, should be considered for final verification. 



In the course of several years of rather diligent collecting, there has 

 naturally accumulated a certain amount of material which cannot be 

 assigned to any of the described species. Some of these specimens are 

 probably color or sexual varieties of forms here discussed; some may be 

 sports, or mutants; a few will likely prove to be new species; but all are 

 ignored in this study. It is ])elieved that no new species should be 

 described in this family unless a good series of both sexes is available, 



