OP ARTS AND SCIENCES. . 169 



ferred to Dictyoneura, shows that the latter certaiuly belong here. 

 The species may be separated thus : — 



1. (Hind) wing at least fifteen centimetres long ; the first offshoots 

 of the scapular branch emitting nervules on the outer side only ; 

 extremities of nervules rather strongly arched. 



T. Fayoli Brongn. Commentry, France. 



1. (Ilind) wing hardly more than twelve centimetres long; the first 



offshoot of the scapular bi'anch emitting nervules on the inner 

 side only ; extremities of nervules rather gently arched , . 2 



2. First offshoots of the scapular branch arising only a little beyond 



the middle of the wing, and some distance before the middle of 

 the scapular branch ; reticulation small and fine. 



T. libelluloides {Diet. Ubelluloides Gold.). 

 Gersweiler, Auerswald (Saarbruck basin). 

 2. First offshoot of the scapular branch arising far beyond tlie middle 

 of the wing, at about the middle of the branch ; reticulation mod- 

 erately large and coarse. Length 7 mm. . T. jucunda, n. sp. 

 Near Pittston, Penn. (R. D. Lacoe, No. 2027). 



LiTONEURA (/Wo9, veupd), n. gen. 



Here are placed the simplest forms in all the group, in which the 

 veins are also comparatively few, simple, and distant. Three species 

 are known : — 



1. Wings small ; fore wing not more than two and a half times longer 

 than broad 2 



1. "Wings large; hind wing nearly four times as long as broad. 



L. laxa {Term, luxa Gold.). Dudweiler (Saarbruck basin). 



2. Some of the veins below the externoraedian forking beyond the 



middle of their course . . . L. obsnleta {Diet, obsoleta Gold.). 



Altenwald (Saarbruck basin). 

 2. None of these veins forking beyond the middle of their course. 



L. anthracophila {Diet, anthracophila Gold.). 

 Gersweiler (Saarbruck basin). 



DlCTYOXEURA Gold. 



In restricting this generic term, which has been applied to nearly all 

 the European species mentioned here, I have employed it for one of 

 the groups whicli contains an original member of the division, as de- 

 fined by Goldenberg, and have selected the one having the largest 

 number of species, and in which the internomedian vein is simple. 



