38 PROCEEDINGS OF THE NATIONAL MUSEUM. vol.59 



Family FORMICIDAE. 



EOFORMICA, new genus. 



Male (apparently). — Of fair size, but with the head small; eyes 

 well developed, convex, placed high up, almost on vertex ; mandibles 

 thick, with at least three sharp terminal teeth; thorax massive, 

 elevated, unarmed, the dorsal profile in lateral view sharply elevated 

 in front and gradually descending posteriorly; wings not preserved; 

 legs slender, with very long femora; petiole of abdomen rather long, 

 gibbous but not much elevated above the highest point (which is 

 broadly rounded in lateral profile) behind the middle; gaster short 

 and rounded. 



Type. — Eoformica eocenica, new species. 



EOFORMICA EOCENICA, new species. 



PlateS, fig. 11. 



Length 7 mm.; thorax 3 mm. long; abdomen 3.1 mm. of which 2.2 



mm. is gaster; length of hind femur about 3.4 mm. Eyes 335 m long, 



about the same distance apart but about 540 m 



from mandibles. Body apparently not hairy. The 



suture at the base of the metathorax is impressed. 



Eocene. "Back of house at Smith's ranch, 



shale of Green River formation, with thin beds 



of oil shale interbedded" (Winchester 17-3, U. S. 



G. S.). Colorado. On the same piece of rock as 



the type Lebia protospiloptera, and 17 mm. from it. 



This may possibly be identical with Scudder's 



Liometopum pingue from White River, Utah. 



fig. 9.— eoformjca eo- The pedicle in Scudder's insect appears to be 



cenica. restorahon different, but it is seen in the dorsal aspect. The 



OF HEAD. ' , . i n 1 



length of hind femora, given as 4.3 mm. by Scud- 

 der, must be a misprint, possibly for 3.4. It is certain that our insect 

 is not related to Liometopum. 



I offer a new generic name for this insect, which seems to be a 

 primitive type related to OecopJiylla; the small head suggests a male. 

 The pedicle, gaster, and slender legs are quite like those of Oecophylla; 

 but the mandibles appear to differ, and if the specimen is a male, the 

 pedicel is very thick for the living genus. Oecophylla is an Old- World 

 genus, so far as at present known. 



I have attempted a restoration of the head of Eoformica, omitting 

 those structures which can not be seen in the fossil. The ocelli are 

 between the eyes instead of far above them as in males of Camponotus 

 and Formica. The margin of the clypeus seems to be denticulate. 



Holotype.— Cat. No. 66932, U.S.N.M. 



