1 88 
Psyche 
[September 
cannot be seen unless the head is tilted forward. In conventional 
full face view the occipital border of the major of yogi is flat or very 
slightly convex (See Plate 12, Fig. 2). Precisely the same explanation 
applies to Wheeler’s statement that the scapes of the major of yogi 
'‘reach the posterior corners of the head”. When the head of the 
major is tilted far enough forward to show the excavated rear border 
of the occiput, it is true that the scapes appear to reach the occipital 
corners. But in conventional full face view they extend beyond the 
occipital corners. It is obvious that tilting the head would not greatly 
affect the configuration of the frontal carinae and, if one is willing 
to unravel the description that both Wheeler and Forel customarily 
applied to lyrate carinae, then these were accurately described. In the 
writer’s opinion this is the only feature in the description of yogi 
which enabled Emery to allocate the species to the subgenus Myrma- 
phaenus for, with strongly lyrate frontal carinae, it cannot belong 
to Colohopsis. 
Finally, there is the matter of pilosity. Wheeler recognized that 
some of the cephalic pilosity of the major of yogi is notably different 
from that on other parts of the body. He gave an accurate descrip- 
tion of the short, blunt, reclinate hairs that arise from the foveolae 
of the clypeus and the adjacent parts of the genae. But he failed to 
mention the erect hairs which occur on the sides of the head from 
the rear border of the eye to the mandibular insertion. These hairs 
also occur on the lateral parts of the gula and over an area extending 
inward toward the antennal fossa. Although short, they are quite 
numerous and form a conspicuous fringe on the anterior half of the 
head. Their structure is unusual for, although each hair is of uni- 
form thickness throughout most of its length, many of them have 
enlarged tips. The enlarged tip is often spherical and such hairs look 
remarkably like the upper ends of insect pins. 
One of the most characteristic features of yogi is the sculpture on 
the front of the head of the major. The surface is rough and covered 
with coarse elevations and depressions which are too broad and ill- 
defined to be called rugae. The roughened areas on the clypeus 
have no fixed direction but those on the genae approximately parallel 
the long axis of the head. Among these roughened ridges are scat- 
tered oval foveolae from which flattened hairs arise, but these are 
difficult to see because the entire roughened surface is evenly covered 
with very fine, densely set, oval punctures which give the area a 
Explanation of Plate 12 
Camponotus (Myrmaphaenus) yogi Wheeler. Figure 1. Head of female. 
Figure 2. Head of major. Both figures drawn to the same scale. 
