1987] 
Shattuck — Pogonomyrmex occidentalis complex 
161 
The P. occidentalis subcomplex 
This group is characterized by the presence of punctures in the 
interrugal spaces of the head; spines or denticles on the propodeum; 
postpetiole with a rounded venter; occipital corners with regular, 
uniform rugae; and frontal lobes only slightly expanded laterally, 
with a thickened border. The 5 nominal species were examined to 
find characters that varied geographically within and/or between 
forms. While many such characters where found, only six varied 
consistently enough to be of value. Each character was divided into 
character states (except Scape Index, which was quantified). Since 
these characters were continuous, division into states was somewhat 
arbitrary. However, the large variation of each character and the 
limited number of states recognized in each allowed ready place- 
ment of most specimens. Before states were assigned, specimens 
were compared with “standard” specimens established for each 
character state. Specimens were initially identified using the con- 
cepts of Cole (1968). Many specimens had been previously deter- 
mined by Cole (primarily from Cole’s personal collection, now at 
LACM), and data were recorded using his identifications. Speci- 
mens not readily determined were recorded, but not utilized in the 
initial analysis. The characters are listed below by their abbrevia- 
tions, followed by an explanation of the character and a list of the 
recognized states. 
Worker Characters and Character States 
Gaster: Base of the first gastric (fourth abdominal) tergum, near the 
insertion of the postpetiole, viewed dorsally. 
1) Very shiny, with no sculpturing. 
2) Very shiny, with faint reticulate sculpturing. 
3) Shiny, with reticulate sculpturing. 
4) Dull, with moderate reticulate sculpturing. 
5) Dull, with heavy reticulate sculpturing. 
PetDor: Dorsum of petiolar node viewed dorsally. 
1) Entire surface covered with fine punctations, transverse rugae 
absent. 
2) Anterior surface with fine punctations; 1 to 2 weak, transverse 
rugae superimposed over punctation on posterior quarter. 
