REVISIONARY NOTES ON THE SANGUINEA AND 
NEOGAGATES GROUPS OF THE 
ANT GENUS FORMICA 1 
By E. 0. Wilson and W. L. Brown, Jr. 
Harvard University- 
In recent years, specialists engaged in ecological and 
regional studies of North American ants have repeatedly 
called upon us to check species identification against types 
and other “historic” material in the Museum of Compar- 
ative Zoology (MCZ). The specialist working away from 
such a collection is likely to assume that the difficulty 
can readily be cleared up by mere comparison of his fresh 
material against the Museum series; unfortunately, such 
comparison by itself rarely produces satisfactory results. 
Of the groups arriving at the MCZ, one causing repeated 
difficulty is the so-called subgenus Raptiformica of For- 
mica. In many ways, it exemplifies the current taxonomic 
conditions within many of our commonest groups of ants. 
The principal fault of the accepted Raptiformica ar- 
rangement lies in an excessive unrecognized synonymy, 
which in turn stems from past failure to appreciate the 
extent of allometric and other normal expressions of intra- 
specific variation. Species such as pergandei and rubicunda 
have been founded in large part on supposed differences 
in head shape, but closer examination shows these and 
other cases to be nothing more than size variants along 
the same general allometric gradient. Trivial variations 
in pilosity, sculpturing, and color have also been much 
overworked in separating “species” ; examination of 
enough material soon reveals most such variation as con- 
tinuously intergradient and broadly bridging the old gaps. 
Another situation bound to give continuing trouble in 
the future concerns the elusiveness of presumed sibling 
species such as F. parcipappa, F. curiosa and F. wheeleri — 
Published with a grant from the Museum of Comparative Zoology 
at Harvard College. 
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