94 FOEMICIB.'E. 



$ . Head without the mandibles rectangular or nearly square, 

 a little broader posteriorly than in front ; the frontal and occipital 

 planes meeting at an acute angle, the occipital plane flat or 

 slightly concave, the sides of the head slightly convex, with the 

 lateral posterior angles distinct but rounded; mandibles elongate 



along the outer, very short 

 along the iuner side, mak- 

 ing the masticatory margin 

 remarkably broad, the apex 

 of tlie mandibles curved back- 

 wards ; antennic 12-iointed, 

 comparatively long and thick, 

 the tlngellum only slightly 

 Fig. 49.— Thorax of g Ccntromyrmcx. and gradually clavate towards 

 a. Mandible. the apex ; antenual carinse 



short, convergent posteriorly, 

 e.xpanded into laminifi over the base of the antennae ; eyes and 

 ocelli absent. Thorax from above broad anteriorly, narrow and 

 compressed posteriorly; the prothorax crescentic, anteriorly sub- 

 margined, the sides and front vertical ; mesonotum convex above, 

 large, circular, the pro-raesonotal suture well marked, the meso- 

 metanotal suture distinct on the sides of the thorax, less distinct 

 above; metanotum saddle-shaped, the basal portion bluutly raised 

 posteriorly, depressed in front, the apical portion obliquely and 

 rather steeply sloped and lightly convex ; legs short aiul stout ; 

 the femora thick, slightly compressed ; the tibia) cylindrical, the 

 iutermediate pair thickly spiued on the upper side as in the fossorial 

 genus Scolia; the tarsi broad and somewhat flat, thickly spiued, 

 the claws minute. Pedicel cubical, truncate anteriorly and pos- 

 teriorly, its posterior face not applied very closely to the basal 

 segment of the abdomen, as in 2Iyopopoiie and Sthpnatoinma ; 

 abdomen elongately oval, anteriorly transverse. 

 $ . Similar, and also without eyes or ocelli. 

 " S ' Mandibles very short, triangular, without teeth. Aiitennse 

 short. Head rounded. Eyes of moderate size. Clypeus \ery 

 convex. Thorax short anti broad. Mesonotum large, with con- 

 verging furrows. The metanotum strongly convex. Pedicel 

 depressed, posteriorly with a node somewhat thin aud emargi- 

 nate above. Abdomen behind the basal segment only slightly 

 constricted. Exterior genital valves triangular, broad, pointing 

 downwards. Pygidium without points. Wings short, not reach- 

 ing the end of the abdomen, hyaline, pubescent, . . . fore wing 

 with 2 cubital, a closed radial, and a discoidal cell."' {Forel.) 



Only a few species of this singular and low form of ant are 

 known. One only has been recorded from within our limits. 



1!5. Centromyrmex feae, Emery (Spakcomyrme.x), Ann. Mus. Cic. 

 Gen. xxvii (1889;, p. 491, pi. 10, figs. 11-15, ?; Forel, Jour. 

 Bomb. N. H. Soc. xiii (1900), p. OOS, ^. 



^ . Entirely yellow, with a brownish or reddish tinge, covered 



