MESOZOIC COCKROACHES. 477 



.straight. The median vein runs parallel to the preceding throughout, has four inferior 

 branches arising tolerably near together just before the middle of the wing, which are 

 very strongly arcuate, simple or forked, apically longitudinal; in the apical third of the 

 wing, distant in origin from the preceding, are a couple of simple longitudinal branches. 

 The anal area cannot extend beyond the basal fourth of the wing. 



Length of fragment 6.7.1 nun.; of wing restored 7.5 mm.; breadth 2.65 mm. The wing, 

 which is scarcely dingier than the chalky-white stone on which it rests, showing its upper 

 domed surface with the slightly dusky veins minutely depressed, is faintly and very del- 

 icately reticulated in the basal half. It comes from the English Purbecks, lies side be- 

 side with the Mesoblattina figured on PI. 46, fig. 3, and was received from Rev. P. B. Bro- 

 clie. It is named for Mr. "W. II. Baily who has interested himself in some, of the fossil 

 insects of Ireland. 



DIECHOBLATTINA gen. nov. ('>-'yj») 



This genus is nearly allied to the last, all the veins of the wing being dependencies of 

 two stocks, which as there pass down the middle of the wing, the veins diverging in op- 

 posite directions; hut here these main stems are very closely approximated and appear to 

 terminate before the tip of the wing, leaving the longitudinal branches only to run to the 

 tip. The humeral Held also is wanting. All the branches, as a mass, are arcuate, the 

 superior ones with the arcuation opening toward the basal half of the costal border, the in- 

 ferior toward the apical half of the same. 



The two species are found in the English Purbecks. 



Diechoblattina Ungeri. 



[Without name] Westw., Quart. Journ. Geol. Soc. Bond., x, 395, PI. 17, fig. 13. 

 Blatta Ungeri Gieb., Ins. Yorw., 322. 



This minute species has much the appearance of a feather. The two main stems run 

 close together in a regular gently arcuate course nearly to the tip, the arcuation opening 

 toward the costal margin. 



Length of wing. o.r> mm.; breadth, 2.5. Lower Purbecks of Durdlestone Bay. 



Diechoblattina Wallacei sp. nov. 



PI. 48, fig. 1. 



Restoring the wing at its broken base, as in the figure, the approximated stems are 

 seen to run in a straight, scarcely oblique course through the basal third of the wing, be- 

 yond which, in more delicate shape, they are regularly and considerably arcuate, terminat- 

 ing in the middle of the very broadly rounded tip. Mosl of the nervulcs are simple, the 

 superior ones rather more crowded than the more strongly arcuate and more longitudi- 

 inal inferior ones, and those arising in the apical half of the wing usually more or less 

 forked. The costal margin is \er\ gently convex, and the apex of the wing roundh 

 docked ; anal area broken oil'. 



