seen to do on some living Blattæ; and we can follow the anal vein, which is nearly straight and extends almost to the end of the wing, together with the axillary veins parallel to it. The remarkable feature which distinguishes this impression from the wings of all other blattids, living and fossil, is the length of the anal nervature and the scant width of the axillary held. Among the blattids of the coal period, the Prognoblattina Fritschii (Heer) and the Gerablattina fascigera (Scudder) have a nervation a little resembling that of our Silurian wing. We propose to name this ancestor of the Blattæ, Palæoblattina Douvillei, in honor of Professor Douvillé.
"Geologists regard as identical the sandstones of May and Jurques
Fig. 5.—Living Blattæ, male and female (Blabera claraziana), from Mexico.
in the Calvados, and place them in the Middle Silurian, while the schists of the Island of Gottland belong to the Upper Silurian. Our blatta-wing, then, must be regarded as older than the scorpion described by Professor Lindström and the other similar scorpion from the Upper Silurian of Lanarkshire."
Besides the engraving of the actual fossil wing in Fig. 3, we give in Fig. 4 an ideal restoration of the same; and in Fig. 5, for comparison, a representation of a living blatta from Mexico, the venation of whose wings nearly corresponds with that of the fossil.
