270 BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY. 



Tenthredo misera, sp. nor. 



Female. Length 17 mm. Large and robust ; head and thorax dark, probably 

 the head was black and the thorax black, varied more or less with brown. Abdo- 

 men pale, very indistinctly indicated in the fossil. Head about two and one-half 

 times as wide as thick. Antennae slender and tapering very gradually to the tip, 

 the joints toward the base of the flagellum three or four times as long as wide. 

 Wings hyaline, the veins rather weak and light in color. Marginal cell long, its 

 cross-vein distinctly arcuate. First submarginal cell considerably narrowed 

 above, the first section of the cubitus being nearly two times as long as the first 

 section of the radius. Second submargiiial cell receiving the recurrent nervure 

 at its basal third. Submedian cell longer than the median by somewhat more 

 than the length of the transverse median nervure. First discoidal cell diagonally 

 about two and one-fourth times as long as the basal vein. Anal cell constricted 

 imperceptibly at the cross-vein, and slowly widened basally behind ; the cross- 

 vein is distinctly oblique. Petiole at apex of anal cell in hind-wing only one- 

 fourth as long as the vein closing the second discoidal cell. 



Type. No. 2048, Mus. Comp. Zool., Florissant, Col. (No. 12,400, S. H. 

 Scudder Coll.). 



This is by far the largest species of Tenthredo here described. 



LYDIDAE. 



Atocus SCUDDER. 



This genus was erected by Scudder ('92) for a single species from Florissant. 

 It comes very close to Neurotoma and Pamphilius as defined by Konow (:05). 

 The only noteworthy character that separates it is the uniformly decreasing length 

 of the autennal joints, the third, or first flagellar, joint being distinctly longer than 

 the second in recent forms. If this character has been overlooked in figuring the 

 type, it can scarcely be considered distinct from Neurotoma, to which it is more 

 closely related than to Pamphilius (= Liolyda) on account of the absence of the 

 humeral cross-vein. 



Electrocephalus KONOW. 



This genus was proposed by Konow ('97) for a single species from Baltic 

 amber. It is related to Janus and Macrocephus. 



Cephus LATREILLB. 



An amber species is noted by Menge ('56), but no other fossil forms have 

 been described or mentioned so far as I am aware. 



