WHEELER, NORTH AMERICAN ANTS 297 



States and the Mississippi Valley, but, as these ants form small colonies 

 and live very secluded lives, their exact distribution cannot be determined 

 at the present time. All four of the forms enumerated in this paper 

 have been taken in Texas. I have seen a single worker minor, which 

 seemed to belong to C. pylartes, from southern Illinois. 



In the following pages, I have given descriptions of all the forms, 

 except those of the fallax and Colobopsis groups, which have been de- 

 scribed in detail in two papers already published.^ As our knowledge of 

 the precise distribution of our North American Camponoti has been very 

 vague and incomplete heretofore, I may be pardoned for citing all the 

 localities from which I have seen specimens, together with the names of 

 correspondents who have most generously assisted me in collecting 

 material. 



The following table will facilitate the identification of the major 

 (maxima) workers.^ 



1. Head of worker major truncated anteriorly ; truncated surface 



circular; intermediate forms (medije) between largest and 

 smallest workers lacking or extremely rare. (A) Subgenus 



Colobopsis 54 



Head of worker major not, or at most very obliquely, truncated 

 anteriorly ; truncated surface not circular ; intermediates 

 nearly always present. (B) Subgenus Campntwtus 2 



2. Head rectangular, as broad in front as behind, obliquely trun- 



cated in front ; each cheek with an irregular longitudinal 



impression bordered laterally by a crenate ridge (53) 



nlcerosiis sp. nov. 

 Head always somewhat narrower in front than behind ; cheeks 



without a longitudinal impression and ridge 3 



3. Anterior median clypeal margin, with a distinct but narrow notch. 38 

 Anterior clypeal margin entire, or at most feebly and broadly 



excised or sinuate in the middle 4 



4. Clypeus carinate 5 



Clypeus ecarinate, or with a very feeble or blunt carina 27 



5. Small species, not more than 6-7 mm. long 37 



Large species, averaging more than 8 mm 6 



6. Anterior clypeal border produced as an angular lobe, wltn a sharp 



point in the middle 7 



Anterior clypeal border more or less produced as a broad trun- 

 cated lobe, with rounded or angular lateral corners and 

 straight or feebly excised or sinuate median margin 8 



' "The American Ants of the Subgenus Colobopsis " Bull. Amer. Mus. Nat. Hist., XX, 

 pp. 139-158, T figs., 1004 ; and "The North American Forms of Camponotus fallax 

 Nylander," Journ. N. Y. Ent. Soc, XVIII, No. 4, 1910. 



' The numbers in parentheses preceding the names of the species, subspecies and 

 varieties refer to the descriptions in the text. 



