THE NEOTROPICAL SPECIES OF THE ANT GENUS 
STRUMIGENYS FR. SMITH: 
MISCELLANEOUS CONCLUDING STUDIES 
By William L. Brown, Jr. 
Department of Entomology, Cornell University 
This paper is a continuation of my series on the New World fauna 
of the dacetine ant genus Strumigenys Fr. Smith. Earlier parts, con- 
taining keys to the abbreviations for measurements and proportions, 
may be found in Jour. New York Ent. Soc. 61: 53-59, ioi-iio 
( I 953 )- In addition to these, other parts have been published in the 
same journal, in Psyche, and in Studia Entomologica, Petropolis, Bra- 
zil. This section is a final one so far as currently available material 
in the genus indicates ; only one more section, which will be composed 
chiefly of an illustrated key to the New World members of the genus, 
is planned at present. 
S. micretes and S. lacacoca 
Following the descriptions of what I called the emeryi group 
(Brown, 1959) the species were discussed as follows: 
“The four species emeryi, never marnii , micretes and lacacoca are 
very close, and seem, from the limited material available, to replace 
one another in a chain extending from Mexico to Panama, and per- 
haps beyond. So far as I can see now, the differences are complex 
enough and strong enough to indicate that each form is a distinct 
species; perhaps together [they constitute] one superspecies. How- 
ever, it is not beyond possibility that one or more of these forms inter- 
grades with a neighbor. More material is needed.” 
Since that writing, material has turned up which, though small in 
amount, tends to bridge the gap between S. micretes Brown and S. la- 
cacoca Brown, indicating perhaps that they belong to a single variable 
species. Nevertheless, the new material poses certain problems itself, 
and the discussion next offered is intended to give details that should 
help in eventually straightening this complex out. 
A sample consisting of parts of four nest series from Boquete, Chiri- 
qui Province, Panama (F. M. Gaige leg., see below) contains 25 
workers with highly variable preapical mandibular dentition, the den- 
ticles varying in number from 1 to 4 in the two mandibles taken to- 
gether, and also varying markedly in size, acuteness and position, so 
as to bridge virtually completely the chief diagnostic character-gap 
between micretes (each mandible with a small but acute preapical 
tooth, and a little farther up a minute denticle) and lacacoca (man- 
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