CARBONIFEROUS ARTHROPOD FAUNA 193 



Its position in this group may be seen by the table given here- 

 with. At any rate, we find here another link connecting the 

 European fauna with that of America. 



Type. Pal. Coll. No. 9243. 



The relationships between the insects of this family can be 

 quickly seen from the following conspectus arranged from the 

 descriptions of the genera : 



Mediastinal vein terminating before the middle of the wing - Cheliphlebia 



Mediastinal vein extending beyond the middle of the wing - - 2 



2. Mediastinal vein extending parallel with the marginal - - - 3 

 Mediastinal extending obliquely to the marginal " ■ - 5 



3. Wings excessively narrow, provided with strong and distant cross- 



veins ---.--. Petromartus gen. nov. 

 Wings less narrow, cross-veins less evident - - - - - 4 



4. All the veins up to the internomedian parallel with the straight margin; 



branches of the internomedian oblique, parallel - Didjanophleps 

 Veins more irregular; scapular branched near the tip - Acridites 



5. Costal margin nearly straight - - - - - - - 6 



Costal margin bowed outwardly ...--.- 7 



6. Mediastinal without oblique branches, scarcely shorter than the 



scapular - - - - . . - - Homothetus 



Mediastinal with branches, extending two-thirds the length of the 

 wing ; scapular reaching nearly to the tip ; cross-veins wanting 



Anthracothremma 



7. Branches of the mediastinal and scapular veins crowded, similar 



Eucaenus 

 Branches of these veins dissimilar, uncrowded - - - - 8 



8. Front wings obovate; branches of mediastinal simple, rather distant 



Gerapompus 

 Front wings less markedly ovate; some of the branches of the 

 mediastinal forked -------- g 



9. Internomedian vein with numerous branches like those of the exter- 



nomedian ...---.- Genopteryx 



Externomedian vein far separated from the scapular, its branches 

 more important than those of the internomedian - Genentomum 



Family Palaeopterina Scudder. 



19. Dieconeura maxima sp. nov. (Plate VI, Fig. 5 ; Plate VII, Figs. 14-16). 



Large, elongate. Wings long, narrow, broadest at the begin- 

 ning of the outermost fourth, costa nearly straight; of the fore 

 wings the mediastinal vein is parallel with and close to the mar- 

 ginal, ending in the scapular somewhat beyond the middle of 



