NORTH AMERICAN NEUROPTERA. 249 



monograph of the earlier stages of the ODONATA. 



Sub-families Gomphina and Cordulegastrina. 

 BY DR. H. A. HAGEN. 



Mr. Louis Cabot has published in the " Memoirs of the Museum of 

 Comparative Zoology" the immature state of the Gomphina 1872 (ready 

 for publication 1871) and of the Aeschnina 1881 (ready for publication 

 1873). As there is no hope of seeing the four other parts published by 

 him, and as the collection has received additions so numerous as to justify 

 a new publication, the first part containing the two sub-families Gomphina 

 and Cordulegastrina (the latter was considered formerly as belonging to 

 the Gomphina) will commence the series. Of the seventeen species de- 

 scribed by Mr. Louis Cabot, only four were raised. The material is now 

 three times as large ; of the forty-eight described species sixteen are 

 raised. The determination of the species is made according to the 

 " Monographic des Gomphines par Edm. De Selys Longchamps," and the 

 four additions to the Synopsis des Gomphines by the same author. These 

 works contain the descriptions of 2-10 species. This paper was ready 

 for publication April, 1884. The help given to my work by other en- 

 tomologists is thankfully acknowledged with each species. 



SYNOF'SIS. 



Tarsi with 2-2-.3 joints Legio GOMPHUS and GOMPHOIDES. 



Tarsi with 2-2-2 joints Legio LIXDENIA. 



Tarsi with .3-3-.3 joints Sub-family COJSDULEGASTRIIVA. 



Hind legs more distant at base than the others Legio GOMPHUS and 



GOMPHOIDES. 

 Palpus not dentated, without terminal hook..HERPETO- and OPHIOGOMPHUS. 

 Palpus dentated, with terminal hook OOMPHUS. 



(The first two genera have the middle third of the front margin of the niask pro- 

 duced in a rounded lobe; the others not; for some exceptions the text is to be 

 compared.) 



Middle legs less distant than forelegs; abdomen prismatic ProgOiil|>hiiS. 



Middle legs and forelegs equally distant; apical third or more of tlie abdomen 

 formed by the thin cylindrical tenth segment Ooiiiphoides. 



Middle legs more distant than forelegs; abdomen flat, circular Ilageiiiiis. 



TRANS. AMKK. KNT. SOC. XII. (36) NOVEMBER, 1886. 



