wheeler: ants of the genus formica. 397 



S. Petiole broad, its superior border rounded, entire or only slightly 



excised in the middle cxsecta var. ctrusca Emery. 



Petiole narrow, its superior border deeply excised in the middle . 9 

 9. Red or sordid yellowish red, posterior portion of head and a 



large spot on the pronotum brown cxsecta Nylander. 



Body paler red, vertex and pronotum each with a small brown 

 spot exsecta var. ruhens Forel. 



10. Gaster with a red spot at the base. 



exsecta pressilabris var. nifomaculata Ruzsky. 

 Gaster without a red spot at the base 11 



11. Gaster, especially at the base, lustrous 



exsecta pressilabris Nylander. 

 Base of gaster opaque, pubescence somewhat longer. 



exsecta pressilabris vars. foreli Emery 

 and exsecto pressilabris Forel. 



FUSCA GROUP. 



Workers. 



1. Palaearctic forms 2 



Nearctic forms 15 



2. Gula without erect hairs 3 



Gula with erect hairs 13 



3. Body opaque or subopaque 4 



Body shining 12 



4. Thorax black, like the head and gaster, in both large and small 



workers 5 



Thorax, at le5.st in the large workers, largely red 7 



5. Body dull and opaque, rather coarsely shagreened. 



fusca var. japonica Motschulsky. 

 Body subopaque, more finely shagreened 6 



6. Pubescence of gaster short, delicate, not silky fusca Linne. 



Pubescence of gaster, long, silky; head, legs, scapes, and sutures 



of thorax reddish or yellowish. . .fusca var. glcbaria Nylander. 



7. Largest workers only with red thorax . .fusca var. rubcscens Forel. 

 Thorax rarely inf uscated except in small workers 8 



8. Erect hairs lacking or very sparse; pubescence delicate and not 



very dense; red portions of body pale 9 



Erect hairs more abundant; pubescence denser, red portions of 

 body darker 10 



