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Show 634 MR. J. WOOD-MASON ON THE FAMILY EMBIID.E. [Dec. 18, mensurately developed veins in the anterior part of each wing is apparently due to a shadow of the radius being cast upon the margin of the brown border of the costa, so as to coincide with the remains of the subcosta ; and Professor Westwood has been the victim of an optical illusion. Affinities.-In anticipation of the full and detailed account of the numerous and important differences between them and the Perlida which is in preparation, and will be published as soon as the drawings needed to render my descriptions intelligible are ready, I may say that the Embiidce undoubtedly belong to the true Orthoptefa, that they are in m y opinion in some respects the lowest term, and in others the lowest term but one, of a series formed by the families Acridioidea, Locustida, Gryllida, and Phasmatida, and that their resemblances to the much lower Perlidce, which may well be direct descendants of a form closely related to Campodea, are due to their low position in the division of Orthopterous insects to which they belong, and do not imply any such close genetic relationship to them as has been suggested. EXPLANATION OF PLATE LVI. Fig. 1. The right anterior wing of a male of Embia (Oligotoma) saundersii, Westwood, X 10. Fig. 1 a. The right posterior wing of the same, X 10. Figs. 2, 2 a. The same wings with all the details omitted in order that the venation may be seen more distinctly:-1, 1, the first or costal vein; 2, 2, the second or subcostal vein; 3, 3, the third or radial vein; 4, 4', 4, the forked fourth or discoidal vein, 4' its rudimentary posterior prong; c, the rudimentary first branch; b, the rudimentary second branch; and a, the termination of its anterior prong (4,4), which is apically anastomosed to the radius, and connected with it by five transverse veinlets in the anterior wings and by three in the posterior ; and 5, 5, the rudimentary fifth or anal vein, which is simple and un-branched and connected with the root of the fourth by a transverse veinlet in both the nearly homonomous wings of this insect. (N.B. All the lines in these figures represent veins, with the exception of that commencing at a point situated a short distance behind the apex of the anastomosed radial and discoidal veins, ending near the origin of the fifth vein, and representing the posterior margin, in which there is no vein.) Figs. 3, 3 a. The same wings with the venation restored by the aid of the brovui bands and triple lines of seta?: e, the lost posterior, and d, the lost anterior fork of the rudimentary posterior prong of the discoidal vein. (N.B. All the lines in these figures represent veins.) Fig. 4. The abdomen of Embia (0.) saundersii $, from above, XlO. Fig. 5. The same from below, X10. Fig. 6. Abdomen of Embia (O.) ndchaeli, M'L., $>, from below, X 3. (N.B. The arabic numerals in the three preceding figures refer to the somites of the abdomen.) |