SCUDDER ON FOSSIL INSECTS. 775 



NEUEOPTERA. 



ODOKATA. 



(LiBELLXJLINA.) 



Fragments of an abdomen in obverse and reverse (Nos. 4175, 4176) are 

 probably to be referred to a species of Libellulina, but they are insufficient 

 to give further determination. They evidently represent four or five of 

 the terminal segments of the body, there being first three segments of 

 equal breadth and a similar length, a little longer than broad, with a 

 slight median carina ; and then three others "without a median carina 

 and with continually decreasing length, the first of them (probably the 

 eighth segment) half as long as the preceding, but of the same width j 

 the next half as long as the one which precedes it, but narrower, and 

 the last still narrower (but imperfect). 



Length of the fragment 20'"™, of its third (seventh? abdominal) seg- 

 ment 4.5""" ; breadth of same 3.5. 



(Ageionina.) 



Dysagrion Fredericii Scudd., Bull. U. S. Geol. and Geogr. Surv. Terr. 

 4, 534-537. — This has already been sufficiently mentioned in the paper 

 cited. 



Podagrion ahortivum. — A second species of Agrionina, at first sight 

 very different from the preceding, proves to belong to the same legion 

 {Podagrion) ; and, so far as its meagre representation by the specimen 

 (No. 4169) goes, to the genus Podagrion proper, agreeing with it in the 

 character of the pterostigma and the supplementary sectors. The speci- 

 men, represents the apical part of a wing with fragments of the middle 

 portion. The pterostigma is a little more than twice as long as broad, 

 and although less oblique on the inner than on the outer side, yet lies at 

 an angle of forty-five degrees with the costal edge, and is therefore more 

 oblique than uspal in Podagrion ; its outer side is arcuate as well as very 

 oblique, but in its entire extent the pterostigma scarcely surmounts two 

 cellules; the outer side is much thicker than the inner, and thickens 

 below as it passes gradually into the lower border, which, like the cos- 

 tal, is much thickened, and appears the more so from being independent 

 of, although in conjunction with, the median nervure. Beyond the ptero- 

 stigma, the ultranodal approaches the principal nervure very closely, so 

 that they are only half as far apart at the margin as below the ptero- 

 stigma ; there are two supplementary sectors, one between the ultranodal 

 and the nodal, arising below the outer half of the pterostigma, the other 

 between the nodal and subnodal, arising slightly further back ; both of 

 these supplementary sectors are straight, but the nodal is slightly undu- 

 lated after the origin of the supplementary sectors ; all the other veins, 



