32 Till-: CANADIAN ENTOMOLOGIST 



A NEW FOSSIL SAWFLY FROM FLORISSANT, 



COLORADO. 



BY T. D. A. COCKERELL, UNIVERSITY OF COLORADO. 



During the latter part of August, of the present year, Dr. 

 J. H. Todd and his son, Dr. J. C. Todd made a small collection of 

 fossils in the Miocene shales at Florissant. On looking over the 

 material, I found one new species, which they kindly presented to 

 the Museum of the University of Colorado. 



Tenthredella toddi, n. sp. 



Length about 8 mm. or a little more (apex of abdomen missing) ; 

 anterior wing 7 mm.; head and thorax black; abdomen pale (prob- 

 ably green in life), with a dorsal black band which is broad basally, 

 sending a branch on each side to or nearly to the anterior lateral 

 corners of the abdomen, posteriori}' rapidly tapering, soon becoming 

 a mere narrow stripe; wings clear, nervures dark; venation as in 

 MacGUlivray's figure of Tenthredella flava (Tenthredo flava Poda) 

 in almost every respect, except that the anal or lanceolate cell of 

 hind wings is petiolate apically (petiole 96 microns long), and the 

 lanceolate cell of anterior wings is joined by the transverse median 

 nervure considerably beyond the middle of the distance from the 

 cross-nervure to the apex. The marginal cell is also decidedly 

 deepsr. The following measurements are in microns: Anterior 

 wing, depth of stigma, 400; end of stigma to end of marginal cell, 

 195'J; second submarginal cell on marginal, 1025; third submarginal 

 on first marginal, 530; third submarginal on second marginal (be- 

 yond crcss-nervure of marginal), 400; basal nervure, 530; first 

 discoidal on second, 800, and on third, G40. Posterior wing: Depth 

 or width of lanceolate cell in middle, 480. 



Among the species described from the Florissant shales, this 

 can only be associated with Tenthredella submersa {Tenthredo 

 suhmersa Ckll.), which is about 13 mm.long.anddiffcrentlycoloured. 

 In the present fauna of Colorado, species of this genus differ in the 

 shape of the third submarginal cell; thus Tenthredella jiavomarginis 

 {Allantits flavomarginis Norton) has this cell short, the upper side 

 no longer than the outer; whereas Tenthredella f err ugineipes (Tenth- 

 redo ferruginei pes Cresson) has this cell much longer. In T. J'oddi 

 the cell is of the longer type. 



January. 191) 



