A NEW AMERICAN AMBLYOPONE, WITH NOTES 
ON THE GENUS (HYMENOPTERA : 
FORMICHUE) 1 
By William L. Browh, Jr. 
Biological Laboratories, Harvard University 
Amblyopone (Stigmatomma) trigonignatha new species 
Figure 1 
Holotype worker: Total length measured from lateral 
profile, mandibles included but sting excluded, 6.12 ± .10 
mm.; Weber’s length of alitrunk, 1.60 ± .05 mm.; maxi- 
mum measurable length of the head from the center of 
the anterior clypeal border to a line connecting the pos- 
terior extremities of the occipital corners, 1.22 ± .005 
mm. ; maximum width of head, 1.05 ± .005 mm. ; cephalic 
index, 86 ± 1 ; left mandible, straightline distance, when 
closed, from the point of contact with the anterior border 
of head to apex, 0.80 ± .01 mm., or, more roughly, about 
two thirds of the length of the head proper. 
Head a little more slender than in A. ( 8 .) pallipes 
(Haldeman), sides gently convex, greatest width at about 
the anterior third, slightly convergent behind and pass- 
ing into the rounded occipital corners through easy 
curves; posterior border of head moderately but dis- 
tinctly concave in outline. “ Amblyoponine teeth” at the 
anterolateral corners of the head reduced to small, 
bluntly rounded tubercles which are more or less hidden 
in dense pilosity; this reduction much greater than in 
any small specimens of the pallipes complex I have seen. 
Clypeus dorsally weakly convex, its anterior apron 
rather narrow, with a very feebly convex anterior border 
which appears straight at some angles of view. This 
apron is rather abruptly terminated on each lateral ex- 
tremity by an angle which marks the boundary between 
1 Published with a grant from the Museum of Comparative Zoology at 
Harvard College. 
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