Biology of the Membra cidae of the Cayuga Lake Basin 203 



The collection in the United States National ]Museum, while in some 

 confusion as to arrangement and difficult of access for systematic purposes, 

 is rich in New York State material and contains valuable representatives 

 of the forms found locally. Dr. Crawford and the late Mr. 0. Heidemann 

 have kindl}^ permitted the author to study this collection and compare 

 local specimens with the museum forms. 



In like manner the collection of' the Philadelphia Academy of Science 

 has been studied with special reference to New York material. This 

 collection, while not extensive, has yielded some valuable data. 



While residing in Buffalo, New York, Mr. Van Duzee extended to the 

 author the privilege of inspecting his very complete private collection, 

 which contains a number of types of the species in question. The en.joy- 

 able visit to ]Mr. Van Duzee's home at that time and the valuable sug- 

 gestions offered then and in later correspondence have been most appreci- 

 ated. 



The author's collection has been built up during the past eight years 

 and contains all but two of the species here mentioned. The collection is 

 strong in having long series of most of the species, the result of extensive 

 collecting in the basin during this period. In most cases the specimens 

 have been compared with types or paratypes and are so labeled. 



The authorities used have been largely the above-mentioned collec- 

 tions, and reports by the authors noted. Mr. Van Duzee's work (1908 a) 

 on the North American forms is the most valuable systematic paper 

 relating to the subject; while the report of Hodgkiss (1910) is reliable for 

 the life-history records of the four species which he discusses. Original 

 descriptions have been consulted in all cases and an attempt has been 

 made to verify the synonymy to date. 



The validity of most of the species has been apparently established. 

 In the few doubtful cases the subject is discussed in connection with the 

 species in question. The study of a long series of specimens of one species, 

 showing much variation and gradation, naturally brings up the question 

 of overlapping, convergence, or hybridizing; but the species are here 

 considered as good unless sufficient data are available to leave no doubt 

 in the matter. It may develoj:) that in the genera Telamona and Cjt- 

 tolobus certain species here recognized will fall, but considerably more 

 biologic proof will be needed before such cases can be established. 



