NORTH AMERICAN NEUROPTERA. 333 



available, I doubt not, that the study of these interesting insects 

 would rival that of butterflies. Our forms have been arranged in 

 seven families. 



Fig. 4.— Dragon Fly. 



I, costal ; 2, subcostal ; 3, median ; 4, submedian ; 5, postcostal ; 6, nodal sector ; 7, sub- 

 nodal sector ; 8, median sector; 9, short sector; 10, upper sector of the triangle ; 11, lower 

 sector of the triangle ; A, arculus ; M, menibranule ; N, nodus; P, pterostigma; a, ante- 

 cubitals ; b, postcubitals ; d, discoidal areolets ; h, hypertriagonal space ; i, internal trian- 

 gle; t, triangle. 



Key to the Families. 



1. — Wings alike, vertical iu repose, eyes peduucled '2. 



VViugs fi''=e'n.Mlar, horizontal in repose, eyes not pedunded 3. 



2." Lv least five antecnbitals CALOPTERYGID^. 



■ But two antecubitals AGRIONID^. 



i— Antecubitals of first and second series not corresponding, except at l)ase....4. 



Antecubitals of first and second series corresponding 5. 



4.~Eyes remote GOMPHID^. 



Eyes touching at a single point CORDULEGASTERID.^. 



Eyes touciiing for some distance ^SCHNID^. 



5.— Eyes tuberclcd behind CORDULID^. 



Eyes not tubercled behind LIBELLULID^. 



Key to the Genera. 



CALOPTERYGIDu®. 



1. — Basal space free, wings broad C'alopteryx. 



Basal space reticulate, wings narrow Hetarina. 



AGRIONID.^. 



1, — Median and subnodal sectors arise almost under the nodus 3. 



Median and subnodal sectors arise nearer tlie arculus than nodus 2. 



2.— Nodal sector arising Ih cells after the nodus Arcliilestes. 



Nodal sector arising 3-5 cells after the nodus L.esles. 



3_ — Bristles on legs very long, each about twice the distance from the base of 



one to the next; larger species .4rgia. 



Bristles on legs much shorter; smaller species .igrioii. 



TRANS. AM. ENT. SOC. XIX. DECEMBEK, 1S92. 



