16 The Ottawa Naturalist. [April 



THE DRAGONFLIES (ODONATA) OF THE OTTAWA 



DISTRICT. 



By E. M. Walker, B.A., M.B., Toronto 



During the past year several small collections of Odonata 

 or Dragonflies from the Ottawa district have been sent to the 

 writer for determination, and at the request of Dr. Fletcher, 

 from whom most of the material has been received, the follow- 

 ing notes upon the species examined have been prepared, and 

 are offered as a basis for future work in this field on the part 

 of collectors in this locality. 



To aid the novice in the determination of his captures, 

 brief mention is made of the characters by which the various 

 families, genera, and species may be most easily recognized, 

 and figures of the characteristic parts are given where these 

 are deemed preferable to verbal descriptions. At the same time 

 the student is reminded that determinations made from such 

 brief descriptions should not be considered final. They may 

 enable him to classify his specimens in a preliminary way, but 

 for accurate and reliable diagnoses recourse should be had to 

 some of the more complete treatises on the group, of which the 

 following will be found the most useful to the beginner: — 



Calvert, P. P. Catalogue of the Odonata of the vicinity 

 of Philadelphia, with an introduction to the studv of this group 

 of insects. Trans. Am. Ent. Soc. 1893, XX, p. 152a-272. 



Kellicott, D. S. The Odonata of Ohio (a posthumous 

 paper, completed and edited by J. S. Hine) Ohio State Acad. 

 Sci., special papers, No. 2, 1889. 



Williamson, E. B. The Dragonflies of Indiana. Dept. 

 Geol. and Nat. Resources of Ind., 24th An. rep't., 1900, p. 

 233-333. 



Needham, J. G. Aquatic Insects in the iVdirondacks, 

 Odonata. N.Y. State Museum, Bull. 47, 1901, p. 429-540. 



Needham, J. G. Aquatic Insects in New York State. 

 N.Y. State Museum, Buh. 68, Ent. 18, 1903, p. 218-279. 



The collections which form the basis of the present paper 

 were made by the following gentlemen: Dr. James Fletcher, 

 Messrs. Arthur Gibson, J. Letourneau, W. H. Harrington, and 

 C. H, Young, and the Rev. G. W. Taylor. Dr. Fletcher tells me 

 that no systematic attempt has been made to collect all the 

 species inhabiting the Ottawa district, but that the material 

 consists chiefly of odd specimens picked up from time to time 

 by the various collectors, while seeking specimens of other 

 orders. This being the case the list, which embraces 47 species, 



