90 THE CANADIAN ENTOMOLOGIST. 



FOSSIL CHRYSOPID^. 



BY T. D. A. COCKERELL, BOULDER, COLO. 



Only six species of Chrysopida3 (Lace-wing Flies) are known in the 

 fossil state. Two of these, from Europe, have only been vaguely reported 

 as Ckrysopa sp.; the other four, named by Scudder, are all from the 

 Miocene shales of Florissant, Colorado. It is even probable that the 

 Florissant species represent all that *is known of extinct Chrysopidae ; 

 because the two European forms, according .to Scudder and Hagen, are of 

 an extremely dubious character, and very likely not Chrysopidae at all. 



Scudder refers the Florissant species to two extinct genera, and it is 

 very interesting to find that both of these belong to the Nothochrysa 

 section, with the third cubital cell divided longitudinally into two sub- 

 equal parts. The genus Nothochrysa^ McLachlan, is to-day represented 

 in this country by a single species, N. Califoniica, Banks, found in 

 California. Of the same section, but with the colours of Chrysopa, is the 

 genus Allochrysa, Banks, with two or three species of the States bordering 

 the Atlantic. These form3 seem to give way to-day to the dominant 

 Chrysopa ; but in Miocene times they evidently prosi>ered, and it is likely 

 that Chrysopa had either not been evolved, or had not reached this 

 country. A specimen found by my wife at Station 14, Florissant, is refer- 

 able to Tribochrysa veiuscula, Scudder, and shows the apical half of the 

 wings, which was missing in Scudder's type. It is evident from the more 

 complete material that this species cannot go in Tribochrysa (the type of 

 which is T. itiequalis^ Scudd.), but allowing for the inaccuracy of Scudder's 

 figure of Pa/ceochrysa, as explained in the text (Tertiary Ins. N. Am., p. 

 167), I think it may fairly be referred to the latter genus, not without a 

 shadow of a suspicion that it is even conspecific with P. stricta, Scudd. 



The following details supplement Scudder's description : 



Paheochrysa vetuscula (Scudder). 

 Anterior wing, 131/^ mm. long ; veins dark, as in Nothochrysa ; the 

 subcosta does not terminate on the margin, as Scudder describes for 

 Palceochrysa, but runs through the stigma, as in Mantispa; 14 costal 

 cells, not counting a series of minute ones at the apical end ; 10 cells 

 between media and radial sector, counting the two long basal ones ; 20 

 cells between radial sector and radius (in Scudder's figure of vettiscula the 

 first cross-nervure is omitted) ; 11 cells between media and cubitus, after 

 the do-ble cell ; six branched nervures from cubitus to lower margin, all 

 in apical part of wing. The media has a direct course, without the bend 

 of Tribochrysa, 



March, iyo8 



