266 BULLETIN: MUSEUM OF COMPAKATIVE ZOOLOGY. 



Taxonus nortoni from the Green River beds of Wyoming. From his figures 

 (PI. 10, Figs. 26-27) of the wing venation there seems to be no doubt that the 

 generic reference is satisfactory. 



Palaeotaxonus, gen. nov. 



Body elongate, subparallel ; the abdomen long, twice the length of the thorax, 

 all its segments of equal width and of nearly equal length. Wing venation as in 

 Taxonus, but the sub median cell is no longer than the median, the transverse 

 median nervure being interstitial with the basal vein. Anal cell divided by an 

 obhque cross-vein which is nearly as long as the trausverse median nervure. 

 Marginal cell long, pointed at the tip, divided by an unusually oblique, curved 

 cross-vein. Second and third submarginal cells each receiving a recurrent ner- 

 vure near the base. 



The present form resembles Taxonus in most respects, but differs very plainly 

 in the interstitial transverse median nervure. This is evidently a primitive trait 

 which is exemplified in several of the other fossil saw-flies here described. 

 On this account I have thought the character to be of generic importance, 

 especially taken in connection with its constancy among large groups of recent 

 Hymenoptera. 



Palaeotaxonus typicus, sp. nov. 



Length 9.5 mm. Head and thorax black, the abdomen more or less rufous or 

 brownish. Head square behind, rounded toward the front, twice as wide as thick. 

 Antennae of equal thickness for at least the basal two-thirds ; black ; the joints 

 not very well differentiated in the specimen, but one somewhat beyond the middle 

 is about four times as long as thick. Wings hyaline, humeral area with a cross- 

 vein just basad to the origin of the basal vein, which is close to the origin of the 



Fig. 7. — Palaeotaxonus typicus Brues. Fore-wing. 



cubitus. Basal vein and first recurrent nervure almost parallel, slightly conver- 

 gent behind. First section of the cubitus twice as long as the first transverse 

 cubitus, which is one-third the length of the second submarginal cell. Third sub- 

 marginal cell over three times as wide at apex as at base. 



Described from two specimens. 



Type. — No. 2043, Mus. Comp. Zool., Florissant, Col. (No. 11,984, S. H. Scudder 

 Coll.). Also, No. 2044, Mus. Comp. Zool., Florissant, Col. (No. 7051, S. H. 

 Scudder Coll.). 



