MESOZOIC COCKROACHES. 475 



c. The mediastinal and scapular veins of the upper wings are amalgamated, 

 and in addition the externomedian vein is amalgamated either 

 ivith the foregoing or with the internomedian vein. 



!N"AKNOBLATTINA gen. nov. (vdvvo<;.) 



In this genus, where all the wings are minute, the externomedian springs from the 

 united mediastino-scapular vein in the second quarter of the wing. The costal field is 

 very broad, while the internomedian area is considerably restricted in width, though it ex- 

 tends a good distance toward the tip. In other respects the different species vary widely. 



The three species come from the upper Oolite of England. 



Nannoblattina similis. 



Corydalis Brodie, Foss. Ins. Engl., 119, PI. 5, fig. 2. 



Blattina similis Gieb., Ins. Vorw., 318. 



In this species the mediastino-scapular area is regularly arched on either side of the 

 middle of the wing and occupies at most more than half its width, while the externome- 

 dian originates nearer the base than in the other species, and leaves a nearly uniform 

 narrow internomedian area. 



Length of fragment (from which a small part of the base only appears to be broken) 

 5 mm.; breadth '2 mm. It comes from the English Wealden. 



Nannoblattina Prestwichii sp. nov. 

 PI. 48, fig. 3. 



A nearly perfect wing, but with the anal area losl and the basal part of the costal area. 

 It is possible, however, to restore the missing border with a considerable degree of pre- 

 cision, and so to judge that the wing was tolerably slender, a little less than three times 

 as long as broad, with straight margins, scarcely tapering, the tip well rounded. The me- 

 diastino-scapular vein is well arched, so that in them iddle of the wing the area occupies 

 nearly half the width; most of its nervules are straight, oblique and simple, but some of 

 the apical ones are forked. The externomedian vein parts from this in the middle of the 

 basal hall' of the wing, and with its forks occupies nearly the entire tip of the wing. The 

 internomedian is rather strongly sinuous, its area narrow excepting at extreme base, the 

 nervules few, simple, slightly sinuous and longitudinally oblique. The anal furrow is 

 pretty regularly and not very strongly arcuate, terminating beyond the middle of the 

 basal half of the wing. An upper surface is exposed on the light brown stone, but it is 

 perfect ly Hat ; it is a little fuliginous, with blackish brown veins which are just perceptibly 

 inrpressed, the anal furrow no more than the rest. 



Length of fragment 6 mm. ; probable length of wing 6.5 mm; breadth 2.25 nun. The 

 specimen comes from the English Purbecks and was studied by the favor of Rev. P. B. 

 Brodie. It is named in honor of the veteran English geologist. 



