176 Scudder — Fossil Insects of North America, 



which must have measured five inches in expanse of wings ; the 

 fragment belongs to an upper wing, embracing all but the base and 

 a slight portion of the tip. 



Dyscritus vetustus is represented by a very small fragment, 

 broken probably from the middle of a wing, near the base, or 

 not far from the division of the middle and anal areas ; but, while 

 its characters are clear enough to distinguish it with certainty from 

 the other specimens, it is impossible to determine either the ap- 

 proximate size of the insect or the family to which it belongs. 



LiTHENTOMUM Harttii was the first specimen discovered by Mr. 

 Hartt. It is a fragment from the central portion of the wing, giving 

 the extension of the principal veins towards the base and along the 

 costal border. Apparently, it does not belong to any family of 

 Neuroptera represented among living forms, but agrees more closely 

 with Hemeristina, a family which I founded upon a fossil insect 

 discovered in Illinois, and of which I shall shortly speak. It differs 

 from Hemeristina both in the mode of division of the nervures and 

 in the peculiar cross-veining of the wing, and probably comes 

 between that family and the Sialina. 1 think that the fragment is 

 a piece of the lower wing, and that the insect, when expanded, 

 probably measured about three and a half inches. 



HoMOTHETUS FOSSiLis is represented by the greater portion of the 

 upper wing ; although it is in a mutilated condition we can determine 

 the extent and character of every principal nervure. At first sight, 

 it seems to be an abnoimal member of the Sialina, but, in reality, 

 it is the representative of another new family, synthetic in nature, 

 combining features of the Odonata and Sialina. These latter families 

 are members each of different groups, and are thought by some 

 naturalists to belong to different orders. The feature which bears 

 the strongest resemblance to the Odonata, and which, in fact, has 

 never been noticed in any other family, is a heavy cross-vein near 

 the base of the wing, between the two principal middle nervures, 

 from which cross-vein new prominent veins take their rise. 



Xenoneura antiquorum is the last, and perhaps the most interest- 

 ing, of all these fossils. It is the basal fragment of a wing, smaller 

 than those which we have mentioned, expanding probably about two 

 inches ; the neuration is peculiar throughout, so that, like the two 

 preceding specimens, it must represent a new family of Neuroptera. 

 The most striking peculiarity is the development of apparently inde- 

 pendent veinlets, forming portions of concentric rings at the base of 

 the wings. There is nothing analogous to it among living Neuroptera, 

 and I can only compare it to the stridulating organ of some male 

 saltatorial Orthopteron. Is it possible that this insect was a member 

 of a group forming a synthetic type between OrthopterasmdNeuropteraf 

 The Carboniferous formation has yielded several localities of fossil 

 insects in America. 



One of these insects was described and figured by Professor Leo 

 Lesquereux^ under the name of Blattina venusta. It is the upper 



1 Owen's Second Report of a Geological Reconnoissance of the Middle and Southern 

 Counties of Arkansas, p. 314, pi. v., fig. 11., 8vo. Philadelphia, 1860. 



