126 TERTIARY INSECTS OF NORTH AMERICA. 



but sixteen species of Libellulidrc, all except one, a Celithemis, referred to 

 Libellula in a broad sense. Nearly every locality where Tertiary insects 

 are found, even including- amber, has supplied its quota of this family, and 

 some localities, such as Oeningen, have furnished the larvae and pupae in 

 great numbers. (1885.) 



The Odonata furnish the first opportunity that my studies have afforded 

 of a comparison between the insect faunas of Florissant and the Green 

 River shales. The Florissant beds have furnished six species in the perfect 

 state besides two larvae ; the Green River shales four species in the perfect 

 state besides fragments of another, concerning which nothing more can be 

 said than that it probably belongs to the Libellulina. Two of the Floris- 

 sant forms belong to Aeschna, besides one of the larvae. All the remainder, 

 four Green River species, and four from Florissant, besides a larva, belong 

 to the Agrionina. The Green River shales are represented by one species 

 of Podagrion and three species of Dysagrion, an extinct genus of the 

 legion Podagrion allied to the genera Podagrion and Philogenia ; the Flor- 

 issant beds by two species of Agrion and two of Lithagrion, an extinct 

 genus with the same alliances as Dysagrion ; the species of H.grion are not 

 sufficiently perfect to decide into what subgenus they will fall, but they 

 are certainly closely related and appear to be most nearly allied to Amphi- 

 agrion or else to Pyrrhosoma or Erythromma. All the Green River 

 species belong then to the legion Podagrion, while the Florissant species 

 are divided between the legions Podagrion and Agrion. The resemblance 

 of the faunas of the two localities is very apparent, though the species and 

 even the genera are wholly distinct. The facies ef both faunas is decid- 

 edly subtropical (October, 1882.) 



Tribe AGRIONINA Hagen. 



This group is the richest of Odonata in the Tertiaries, both in Europe 

 and America, but curiously the legions into which it is divided by de Selys 

 are very differently represented in the two countries. To establish better 

 terms of comparison I have given some attention to the descriptions and 

 figures of the mature European forms, and their study brings out some 

 interesting points. 



In Europe the legion Lestes is far the best represented ; into this fall 

 Lestes coloratus Hagen from Radoboj, first figured by Charpentier, Agrion 



