114 PROCEEDINGS OF THE ACADEMY OF [1885. 



course, and fork with tolerable abundance, filling the space with 

 graceful lines, spreading like (sinuous) rays of a fan. The 

 genus is closely related to Neorlh rdblattina of the American Trias 1 

 but differs from it in the much greater area covered by the amal- 

 gamated mediastinal and scapular veins. 



The following described species may be referred to it: — 



Rithma purbeccensis Gieb., Faun. d. Vorw., iii, 319. Figured by Westw., Quart. 

 Journ. (Jeol. Soc. Loud., x, PI. 18. fig. 32. Lower Purbecks, Durdlestone Bay, 

 England. 



Rithma Morrisi Gieb., Faun. d. Vorw., iii. 319. Figured by Westw., Quart. Journ. 

 Geol. Soc Loud., x, PI. 18, fig. 34. Lower Purbecks, Durdlestone Bay, England. 



Rithma formosa, 



Blattina formosa Ilcer, Lias Ins. Aarg., 15, PI. IT, figs. 41, 42 ; liter, 

 Urw. Schweiz, PL 7. figs. 1, \b, ; Lias, Schambelen, Switzerland. 



Rithma liasina. 



Blattina Hasina Gieb., Faun. d. Vorw., iii, :;17. Figured by Brodie, 

 Foss. Ins. Engl., PL 8, fig. 12; Lower Lias of Wainlode, Strensham, 

 England. 



MESOBLATTINA, 



proposed by E. Geinitz, as stated, for two Liassic species of 

 continental Europe, is a most prolific type, a considerable num- 

 ber of English mesozoic forms falling here, and among others, as 

 remarked above, those figured by "Westwood and described by 

 Giebel under the names of Rithma Murchisoni and R. antiqua. 

 The former of these, as well as a considerable number of new 

 species have been sent to me by Mr. Brodie. In this genus the 

 basal sweep of the externomedian and internomedian veins is very 

 noticeable, following as they do the curve of the anal furrow 

 before branching to fill the lower half of the wing. In this 

 respeel they remind one strongly of Elisama, but the wings are 

 much slenderer than there, and what is of more importance the 

 anal area isof the normal size, while next the humeral angle is seen a 

 flat unveined Held, so frequent in modern cockroaches. To this 

 belong among others the following species: — 



Mesoblattina protypa Gein., Zeitschr. Deutsch. Geol. Gesellsch., 1880, 519-20, PL 

 22, fig. I. Litis of Dobbertin, (lermany. 



Mesoblattina angustata Gein-, ih., 5 10-20. 



Blattina angustata Beer, Viert. naturf. Gesell. Zurich, ix, 288, 299-800, 

 PL fig. <». Lias of Schambelen, Switzerland. 



