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PROGRESS IN OUR KNOWLEDGE OF THE ODONATA 

 FROM 1895 TO 1912. 



By Philip P. Calvert, Ph.D., 



University of Pennsylvania, Philadelphia, Pa., U.S. America. 



At the third International Congress of Zoology, held at Leyden, 

 September 1895, a memoir entitled Le Progrès dans la Con- 

 naissance des Odonates was presented by M. le Baron Edmond 

 DE Selys-Longchamps, the most eminent authority on this 

 group of insects. For reasons which he gives, de Selys was 

 obliged to limit himself to a succinct sketch of the evolution of 

 the taxonomy of the Odonata. 



The seventeen years which have elapsed since the Congress 

 of Leyden have seen the publication of man}' researches dealing 

 with the insects known as Dragonflies, Libellules, or Libellen, in 

 three principal European languages. A Congress of Entomology 

 seems an especially fitting occasion on which to summarise the 

 results of these investigations. The following lines will there- 

 fore attempt a review of what seems to be the most important 

 work done between 1895 and 1912, not only in taxonomy, but 

 also in the other divisions of the entomology of the Odonata. A 

 brief outline of the systematic literature from the time of 

 LiNN.EUS to the close of the nineteenth centur}^ was pubhshed 

 by Mr. Kirby in 1901. 



Our views of the relationships of living beings to each other, 

 of their evolution into their present forms, and of the values of 

 the characteristics by which we judge these relationships, are 

 changed from time to time as our knowledge of structure and 

 ontogeny increases. During the period which we here discuss, 

 several important contributions to the morphology and embry- 

 ology of the Odonata have appeared. 



