344 SAMUEL H. SCUDDER OX THE 



Gerarus Cy e P a P<>'s) gen. nov. 



Body slender and elongated, the prothorax rapidly narrowing in front, so that the head 

 is probably narrow and elongated. Wings correspondingly slender, well rounded, but with 

 tips not produced. Mediastinal vein at a considerable distance from the front margin, 

 united to it by many arcuate cross veins, and extending a variable distance toward the tip, 

 but always to some distance beyond the middle. Scapular vein with a considerable num- 

 ber of longitudinal, more or less oblique, simple or forked offshoots, making it by far the 

 most important vein in the wing, the internomedian and anal veins apparently dividing the 

 remaining space about equally between them. 



G-erarus vetus, sp. nov. PI. 31, fig. 6. 



The mesothorax appears to be broader than long, the prothorax rounded subtriangular, 

 and in front of it a linear prolongation more than three times as long as broad, which may 

 be the head, or a prolongation of the prothorax ; in front of this the stone shows a black- 

 ish discoloration. The wings are broadly rounded at the apex. The mediastinal vein ex- 

 tends nearly or quite to the tip ; the scapular vein, arcuate and separating itself gradually 

 from the former, again sweeps toward it past the middle of the wing, and throws off a large 

 number of mostly simple, parallel, oblique branches, the earliest of which must strike the 

 lower margin not far from the middle of the hind margin ; transverse cross veins are to be 

 seen throughout in the minor interspaces. Length of whole preserved portion 71 mm., of 

 head (?) 11 mm., breadth of same, 3 mm., breadth of mesothorax 10 mm., length of 

 wings 52 mm., breadth across the partly opened wings 23 mm., breadth of wing 19 mm. 



Mazon Creek, 111. Received from Mr. J. W. Pike and now in the collection of Mr. R. 

 D. Lacoe under the number 2054. 



A much smaller but very imperfect fossil, figured on pi. 32, fig. 3, appears to belong in 

 this neighborhood, but to be distinct from anything known. Nearly all the numerous ner- 

 vules of the scapular and lower veins are straight, simply and early forked, parallel and 

 oblique. A future find may enable us to place it more exactly. The length of the frag- 

 ment is 30 mm., the probable length of the wing about 40 mm., and its probable breadth 

 about 15 mm. It comes from Mazon Creek and bears the number 2016 in the cabinet of 

 Mr. R. D. Lacoe, to whom 1 am indebted for the opportunity of seeing it. 



Gerarus mazonus. sp. nov. PI. 32, fig. 7. 



The body is much elongated, but is very imperfectly preserved, patches only or obscure 

 indications of it appearing at various places. There seems to be a transversely rounded 

 granulated prothorax, in advance of which is a longitudinally ovate head, shaped like that 

 of Eugereon, and in advance of that the base of a tube-like prolongation, which is almost 

 immediately broken at the end of the nodule in which it is embedded, and is half as broad 

 as the head. The abdomen is slender and the wings long and slender with scarcely pro- 

 duced rounded tips. The neuration is imperfectly preserved, and in some parts it is diffi- 



