1984] 
Wheeler — Behavior of Proeryptoeerus 
189 
food and high rates of regurgitation are adaptations to dry condi- 
tions (Wilson, 1976; Cole, 1980), and would not be necessary in C. 
atratus which nests in moist tree cavities (Corn, 1976). The relatively 
wide nest chambers of C. atratus may have provided an environ- 
ment in which the primitive behavior of carrying nestmates was 
possible, and ultimately, retained (Corn, 1976). The lack of both 
infrabuccal pellets and abdominal trophallaxis may be indicative of 
an entirely different diet in C. atratus than either P. seahriusculus or 
Z. varians. 
In summary, some of the behavioral similarities between P. sea- 
hriuseulus and Z. varians, and the apparent divergence of C. atratus, 
may be based in ecology rather than phylogeny. Behavioral conver- 
gence of P. seahriuseulus and Z. varians would lend further support 
to cladogram A . 
Summary 
P. seahriusculus is a cephalotine with multiple queens and a 
monomorphic worker caste. Differences in the behavior among 
individual queens suggest that queens are not equal in reproductive 
status. Newly emerged P. seahriusculus workers indulge in pro- 
longed periods of abdominal trophallaxis. Abdominal trophallaxis 
has been reported previously in Z. varians, an advanced cephalotine 
with a dimorphic worker caste. Cladograms based on behavioral 
characters support a phylogenetic scheme in which the divergence of 
Proeryptoeerus occurred prior to the divergence of Cephalotes. 
Within the Cephalotini, the minor workers, rather than soldiers, 
appear to be the novel worker caste. 
Acknowledgements 
I would like to thank all the Eberhards for encouraging me to 
work in Costa Rica and for making this study not only possible but 
pure pleasure. L. Freed helped me locate, and provided transporta- 
tion to cephalotine habitats in Panama. I thank N. F. Carlin, D. S. 
Gladstein, and R. M. Fagen for guiding the analysis of the reper- 
toire and W. P. Maddison for enlightening discussions of cladistics. 
N. F. Carlin, B. Holldobler, W. P. Maddison, and E. O. Wilson 
provided constructive comments on earlier versions of the manus- 
cript. Funds were provided by a Smithsonian Postdoctoral Fellow- 
ship and NSF Grant #PCM-8301763. 
