SCUDDER ON TERTIARY INSECTS. 531 



broadly excised, so that its middle is straight and the lateral angles are 

 rather sharply angulatej the hind margin with very oblique sides, so 

 that if continued they would form less than a right angle with each 

 other, but toward the middle line incurved, so that the thorax is rounded 

 posteriorly and excised in the middle. Scutellum very small, scarcely 

 more than lialf as long as the thorax and rather longer than broad,, 

 tapering more rapidly in the basal than in the apical half. The fore 

 tibisB apparently unarmed, and of the same length as the fore femora j 

 the apical tarsal joint of same legs tumid, longer than the other joints 

 combined, of which the second is less than half as long as the basal 

 joint, the whole leg only a little longer than the breadth of the tegmiuaf 

 fore coxae apparently in close proximity. Tegmina large, nearly equal 

 throughout, the inner base angularly excised next the posterior border 

 of the thorax, the apex well rounded, a little produced anteriorly; it 

 was apparently coriaceous, with little mark of any excepting some of 

 the principal veins, which are elevated. The base of the costal part of 

 the wing is so expanded, to give equality to the wing, that the radial 

 vein at its base is very near the middle of the tegmina, and continues so 

 until it forks in the middle of the basal half of the tegmina ; its lower 

 branch continues its course subparallel to the costal margin, while the 

 upper branch curves upward, and follows close to the costal margin, 

 until, like its fellow, it is lost in the membrane near the tip of the teg- 

 mina ; the sutura clavis runs straight to the posterior border beyond the 

 middle of its outer half, and midway between the two the radial origi- 

 nates, forking almost immediately, the forks dividing the inner area 

 equally between them, and in the middle of the outer half of the teg- 

 mina united to each other by a cross-vein, to which they bend ; they too 

 are lost before the tip. The wings are not sufiticiently preserved to 

 characterize, beyond mentioning that the upper three nervules agree with 

 StaVs figure of Liorhina, excepting that the third is not united apically 

 with the fourth by an elbowed marginal vein, although it diverges api- 

 cally from it. Abdomen more than twice as long as the rest of the 

 body, tapering regularly to a pointed extremity. 



Petrolystra gigantea. — Two nearly perfect specimens (Nos. 411, 412,) 

 reverses of each other, were picked up by a child just as I reached the 

 quarries at Florissant, and another, a fragment of a wing (No. 11,241), 

 was afterward found in the same place. The head was apparently 

 dark-colored, the thorax not so dark, delicately and softly shagreeued 

 with a slight median carina. The tegmina are almost similarly rugu- 

 lose ; the costa of the same is pretty strongly convex at base, very 

 slightly convex beyond the middle of the basal half; the posterior bor- 

 der is slightly excised at the tip of the clavus, and the outer margin is 

 oblique, being angularly excised at the posterior angle, although rounded 

 throughout. It was dark, darkest at base and gradually growing- 

 lighter, more fuliginous toward the tip (although all the specimens do 

 not show this), and traversed by four equidistant transverse pale bandS;^ 



