CLASSIFICATION OF PALEOZOIC INSECTS. 327 



Anthracothremma robusta. sp. nov. PI. 30, fig. 1, •">. 6. 



The surface of the body in the specimen illustrated in fig. 6 is not well enough pre- 

 served to show much texture, but the head appears to have a median suture and to taper 

 rapidly to a rounded front in advance of the lateral eyes. The prothorax, although very 

 short and transverse, tapers rapidly in front ; the mesothorax is a little larger and longer 

 than the metathorax, which does not exceed the abdominal segments in length. The 

 front wings are three and a quarter times longer than broad, with the costa very straight 

 excepting at the extremities ; the stiffness of the wing, however, is relieved by the arcuation 

 of the principal veins; the branches of the mediastinal vein are simple, oblique, a little 

 curved, not crowded ; those of the scapular vein are few in number, lie wholly beyond the 

 mediastinal and are rather vague ; those of the externomedian vein are nearly straight, on 

 one wing about half of them forked at varying distances along the stem, on the other wing 

 in the single specimen at hand most of them simple, and one transferred from the main 

 stem to a forking branch ; they are equidistant and not closely crowded. Legs stout and 

 flattened. Length of body 30 mm., of head 3.25 mm., of prothorax 1.5 mm., of entire 

 thorax 6.25 mm., of abdomen 19 mm., breadth of head 4 mm., of thorax 10 mm., of last 

 segment of abdomen 5 mm., length of front wings 28 mm., breadth of same 8.65 mm. 



Mazon Creek, 111. Carboniferous. Collection of Mr. R. D. Lacoe, No. 2048. 



Another specimen (figs. 1, 5) is better preserved in some parts, showing the texture of 

 the body to have been uniformly and delicately granulose. The borders of the head are 

 imperfect so that the drawing may here be incorrect. The tip of one of the wings is 

 better preserved so that the form ca,n be better determined. Nothing additional can be 

 gained from the neuration. It comes from the same locality and bears in Mr. Lacoe's 

 collection the number 2052. 



G-enopteryx (-y'vos, -m-ep^) gen. nov. 



Wings obovate, with more or less arched costa, and somewhat produced apex ; medias- 

 tinal vein of variable length, the scapular extending to or nearly to tiie tip, connected to 

 the veins on either side of it by transverse or oblique cross-veins ; externomedian vein very 

 important, commencing to branch considerably before the middle of the wing and by 

 several longitudinally oblique mostly forked veins, closely connected by feebler cross 

 veins, feeding the aj)ex of the wing; internomedian vein also important with several 

 similar veins, the outermost of which runs in close proximity to the basal externomedian 

 branch from its very origin, so that at first sight both externomedian and internomedian 

 branches appear to spring from a common vein. 



G-enopteryx constricta, sp. nov. PI. 2'J. fig. 11. 



A single broken wing is preserved with part of another, probably of the same side. It 

 conforms best to the generic characters laid down above in the similar appearance of the 

 externomedian and internomedian branches, which are all less longitudinally disposed than 

 in G. lithantliraca. Another marked distinction from that species is in the comparative 

 narrowness of the area of the wing above the scapular vein, due partly to the less strongly 



