726 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. xxix. 



ARCHOBLATTINA Sellards. 



Front wing nciirly olli])tical, 'Jj times as lon^^' as hroad. Costal aiva 

 extending- about two-thirds the length of the wing, not expanded, with 

 numerous, mostly compound veins. Superior oti'shoot of the radius 

 more strongly l)ranched than the inferior one, which is given oti" near 

 the base. All branches of the radius end in the anterior margin. 

 Media with 2 (or 8?) compound branches running off forward. Cubi- 

 tus strongly vaulted, with many (about 1>) mainly furcate veinlets, 

 w hich take up the entire free inner border. Anal area wide, occupy- 

 ing two-tifths the length of the wing, with ruunerou.s veins. Pronotum 

 not broader than long and of nearly pear-shaped outline. Very large 

 forms. 



Type of geiuis, Archohlattina heecJieri (Sellards). 



ARCHOBLATTINA BEECHERI Sellards. 



Mf(/(ihlattinn heecheri Sellards, Amer. .Tour. Sci. (4), XY, 190.3, p. 812, pi. viii. 

 Archohlattina heecheri Sellards, Amer. Jour. Sci. (4), XVTII, 1904, p. 218, fipfs. 

 30, 31, 32. 



Locality. — Mazon Creek, near Morris, Illinois. Pennsylvanian; 

 Kittanning? (Allegheny) stage. 



The length of the front wing of this gigantic form amounts nearly 

 to 70 mm. 



The name Megablattina., being preoccupied, was changed by Sellards 

 himself to Arch.ohlattm a . 



? ARCHOBLATTINA SCUDDERI, new species. 



Bhittina si>. SciTDDER, Bull. V. S. (leol. Snrv., No. 124, 189.^, p. 142, pi. xii, tig. T) 

 (not. pi. x, tig. 16). 



Locality. — Mazon Creek, near Morris, Illinois. Pennsylvanian; 

 Kittanning? (Allegheny) stage. 



A hind wing, about 55 mm. long, with numerous cross veins, wdiich 

 possibly may belong to the preceding species. 



ILolotype.^Q,2,t. No. 38105, U.S.N.M. 



GYROBLATTA, new genus. 



Front wing 2^ times as long as l)road, with very strongly curved 

 front margin, and nearl}' straight posterior border, therefore nearly 

 semicircular in form. The rather broad costal area reaches three- 

 fourths the length of the wing, and contains about 7 many-times 

 branched o]>lique offshoots, some of which are given off' at the base. 

 The radius forks very near the })ase of the wing and its superior branch 

 separates into -i to <! twigs; the inferior, on the other hand, into 2 to 5. 

 The media sti-etches in a strong vault to the inner border and sends 

 off' 3 to 4 long, more or less divided, branc^hes horizontally foi-wai'd to 



