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[Vol. 91 
nately, not known. Therefore, cephalotines are compared with other 
myrmicines, when that information is available, as well as with 
other subfamilies. Two important behaviors, abdominal trophal- 
laxis and stridulation (see Table 3), were discussed in detail above. 
Adult transport, in which one adult carries another, occurs widely in 
ants, and is especially well developed and stereotyped in the Myrmi- 
cinae and the Formicinae (Wilson, 1971; Moglich and Holldobler, 
1974). Therefore, the expression of this behavior is considered the 
primitive condition in the Myrmicinae and its loss the derived state. 
Behavioral Cladograms 
Cladograms provide a useful device for examining possible ways 
different sets of characters could have evolved. I will assume that the 
three species, P. scabriusculus, C. atratus, and Z. varians, are 
monophyletic, sensu Hennig (1966); no species is an ancestor of 
either of the others. 1 also assume that the three species involved are 
representative of their genera. Recognizing that this second assump- 
tion may be premature, 1 stress that more species need to be studied, 
especially in the diverse genus Zacryptocerus. 
The most useful characters in constructing cladograms are those 
that are synapomorphic, derived traits that are shared. There are 
three ways that three species could have evolved such that two now 
share an advanced trait. The simplest is that the two species share a 
common ancestor that possessed the character. The second and 
third ways require two steps. First, the two species could have 
evolved the trait independently. Secondly, all three species could 
have acquired the trait from a common ancestor, and one species 
subsequently lost it. 
There are four synapomorphic characters in Table 3. Abdominal 
trophallaxis and absence of adult transport are shared by Z. varians 
and P. scabriusculus while absence of stridulation and of abdominal 
self-grooming are shared by Z. varians and C. atratus. Of the three 
possible cladograms using these four traits (Figure 2), two appear 
equally plausible. In both cladogram A and B , two of the four 
synapomorphies require two steps to generate the appropriate dis- 
tribution of characters. Two steps means independent derivation of 
the characters, or common derivation and secondary loss. The third 
cladogram, C, can be rejected as unlikely by parsimony since all 
four synapomorphies require two steps to produce the appropriate 
pattern. 
