5 GEORGE V. SESSIONAL PAPER No. 39b A. 1915 



IV. 



REARING EXPERIMENTS AND ECOLOGY OF GEORGIAN 



BAY EPHEMERIDAE. 



By W. A. Clemens, Department of Biology, University of Toronto. 



(Plates XIII and XIV and 1 figure in the text) 



The results given in the present paper are based upon a series of observa- 

 tions on the distribution and life histories of various species of this family, 

 which were begun on the advice and under the supervision of Dr. E. M. 

 Walker. Owing to the very imperfect knowledge of these species as 

 they occur in Canadian localities, it was considered desirable to make 

 collections of the local forms occurring in the vicinity of the Biological Station 

 and to conduct breeding experiments to determine the identity of nymphs and 

 imagos, and discover the time of emergence. These insects, as is well-known, 

 are an important source of fish food. In view of the comparative abundance 

 of the species of Heptagenia occurring in this region, however, and the excep- 

 tional facilities for their study, it was decided to deal with these species in a separate 

 paper which appears elsewhere. 



The life histories of comparatively few North American forms, comprising 

 in all about 31, out of a total number of about 114, have been described. The 

 first was that of Baetisca obesa Say, by Walsh in 1864. In 1901, Professor J. G. 

 Needham reared and described six species; in 1904 he published the life histories of 

 11 more, and since then 2 others. In 1903, Mr. Edward Berry described the life 

 histories of 3 forms and in 1911 Dr. Anna Morgan described 8. 



The particular species are as follows: Needham (1901, 1904) Heptagenia 

 pulchella Walsh; Baetis pygmea Hagen; Siphlurus alternatus Say; Caenis diminuta 

 Walker; Hexagenia variabilis Eaton; Ephemera varia Eaton; Chirotenetes albo- 

 manicatus Needham; Ameletus ludens Needham; Choroterpes basalis Banks; Calli- 

 baetis skokiana Needham; Ephemerella bispina Needham; Tricorythus allectus 

 Needham; Leptophlebia praepedita Eaton; Heptagenia interpunctata Say; Ecdy- 

 urus maculipennis Walsh; Polymitarcys albus Say; (By W. E. Howard) ; Ephemerella 

 dorothea Needham; Potamanthus diaphaniis Needham; Berry (1903); Leptophlebia 

 amencana Banks; Blasturus cupidus S&y ; Callibaetisferrugineus Walsh. 



Morgan (1911) Ephemerella cornuta Morgan; Ephemerella rotunda Morgan; 

 Ephemerella serrata Morgan; Ephemerella lata Morgan; Ephemerella tuberculata 

 Morgan; Ephemerella deficiens Morgan; Ephemerella plumosa Morgan; Ephemerella 

 spinosa Morgan; Iron fragilis Morgan; Epeorus humeralis Morgan. 



As for Canadian forms, L'Abbe L. Provancher, in 1877, recorded the following 

 from Quebec; Ephemera simulans Walk.; Hexagenia bilineata Say.; Heptagenia 

 terminata Walsh; H. canadensis Walker; H, quebecensis Provancher; Siphlurus 

 396—8 11 



