1966] 
Creighton and S netting — Camponotus 
191 
aberrant than yogi when compared to species in the truncatus-im- 
pressus complex. With this in mind the question is not whether 
Wheeler was justified in placing yogi in Colobopsis but whether 
Emery was any better off when he transferred it to Myrmaphaenus . 
At present no final answer can be given for both subgenera are un- 
usually heterogeneous. Nevertheless we prefer Emery’s treatment for 
the following reasons: 
( 1 ) It is quite impossible to relate yogi to the truncatus-impressus 
complex in Colobopsis. 
(2) If yogi is assigned to Colobopsis it will have to be placed in 
one of the Old World groups which are, at present, too ill-defined to 
permit certainty of assignment. 
(3) There is no feature of yogi which would prevent its inclusion 
in Myrmaphaenus and it possesses several features which indicate that 
it fits better in that subgenus than in Colobopsis. 
Most of these features have been mentioned above but one of them 
merits a more detailed discussion. The head of the female of yogi 
resembles that of the media rather than that of the major. In full 
face view the head of the major is as wide (in some specimens slightly 
wider) at the level of the rear of the clypeus as it is at the anterior 
border of the eyes. This gives the head a distinctly rectangular out- 
line, for the sides turn in toward the mandibular insertions abruptly 
below the level of the middle of the clypeus. In the female and 
media the sides of the head converge gradually from the level of the 
anterior border of the eyes to the mandibular insertions. Thus in 
full face view the anterior half of the head is distinctly narrower 
than the posterior half (See Plate 12, Fig. 1). There are sculptural 
differences as well, for the female and the media lack the roughened 
areas on the clypeus and its surface, as well as that of the truncated 
parts which flank it, is granulo-shagreened only. The roughened 
ridges are present on the sides of the head but they are feebler than 
those of the major and the oval foveolae show more plainly. 
A comparable condition is found in C. (Myrmaphaenus) andrei 
Forel, which occurs on the Mexican plateau. Moreover, the major 
of andrei is remarkably like that of yogi, both in the anterior trun- 
cation of the head and in the structure of the clypeus. 3 Since andrei 
has a strongly polymorphic worker caste it would appear that we are 
reaching some uniformity in the species assigned to Myrmaphaenus. 
At least we have in yogi, andrei and ulcerosus three species where 
3 The insect which Forel described as the major of andrei is actually a 
media. Neither he nor Wheeler ever saw the major of andrei, which is a 
very distinct caste. 
