(518 TERTIARY INSECTS OF NORTH AMERICA. 



F(.)RMICA Linne. 



Formica arcana. 



PI. 3, Fig. 24. 



Formica arcana Scudd., Rep. Progr. Geol. Surv. Can., 1875-1876, 266-267 (1877). 



A single fragment of a wing, exhibiting, however, all the important 

 parts of the neuration, is to be referred to the genn.s Formica (s str.) 

 Pimpla senecta lies on the same stone. The discoidal cell is of medium 

 size, subquadrate, a little broader below than above ; the single closed 

 cubital cell is about three times as long as the discoidal cell, being a little 

 produced (to considerably less than a right angle) at the tiji, where the 

 transverse vein, coming obliquely from the stigma, strikes the cubital vein 

 exactly where it branches, forming a minute stigma, from which four veins 

 radiate almost symmetrically; the wing is of a uniform, faint fuliginous 

 color, the stigma of medium size, darkest along its lowest border, and all 

 the veins dark, the scapular vein even black, and margined on its apical 

 half with testaceous. 



The wing is 3"'™ in width, from the anal emargination to the base of 

 the stigma, and the tip of the basal internomedian cell is 4.25"™ distant from 

 the apex of the closed cubital cell, making it probable that the entire length 

 of the wing was nearly 12"™. 



Quesnel, British Columbia. One specimen. No. 10" (Dr. G. M. Daw- 

 son, Geological Survey of Canada). 



LASIUS Fabricius. 



LaSIUS TERREt'S. 



PI. 10, Fig. 23. 



Laxiiis tn-reus Scudd., Bull. U. S. Geol. Geogr. Surv. Terr., IV, 747-748 (1878). 



A single specimen obtained by Dr. Hayden at the " Petrified Fish Cut," 

 Green River (alluded to in his Sun Pictures of Rocky Mountain Scenery, 

 page 98), is probal)ly to be referred to this genus, but is in rather a poor 

 state of preservation. The head is small and rounded, with antennae shaped 

 as in Lasius, but of which the number and relative length of the joints can 

 not be determined from their obscurity ; the long basal joint, however, ap- 

 pears to be comparatively short and uniform in size, being not quite so long 

 as the width of the head, while the rest of the antenna" is more than half as 



