PRE FAC E, 



Up to this time seven species only have been described by H. Hagen. One from 

 Brazil, Gynacantha spec. ; the others from Europe, Anax f ormosus ; ^schna ruf escens, 

 grandis, cyanea, affinis ; Brachytron pratense. 



There have been figured before, — 



>. Anax formosus ; Muralto ; Drury ? Evans ; Dufour. 



^schna cyanea ; Swamerd ? Frisch ? Eeaumiir ; Donov ; Dufour. 



-(Eschna mixta ; Eeaum ? 



.iEschna grandis ; Eoesel ; De Geer ; M. Harris. 



^schna rufescens ; Dufour ? 



^schna constricta ; Sanborn. 



In all six species, three only, however, are recognizable, and none of the figures are 

 accurate enough for specific determination. Of the twenty-four species now described 

 and figured, containing the types of the seven species described by H. Hagen and 

 others, there are of 



Europe, nine. 



America, nine ; seven from U. S. A. 



Asia, four. 



Africa, one. 



Half of the species described were raised, viz., the nine European species and three 

 United States species. The actual number of described species of ^Eschnidfe has not been 

 exactly ascertained, but the twenty-four immature states given are about one tenth. In 

 the United States there are twenty-one species knowni ; of these, seven in the immature 

 state are given. In Europe, thirteen are known ; of these, nine in immature states are 

 given. To make any general remarks on the classification of Gomphina and Jilschnina 

 has been found impossible, until the Libellulina and Cordulina have been described. 



