192 
Psyche 
[September 
the worker caste is polymorphic, the front of the head of the major 
is truncated, the clypeus of the major is flat and ecarinate or nearly 
so, the anterior border of the clypeus of the major is distinctly (often 
deeply) impressed and the head of the female resembles that of the 
media. These three species form a reasonably compact geographic 
group, since yogi occurs in southern California, ulcerosus in western 
Texas, southern Arizona and northern Chihuahua and andrei in 
Durango, Zacatecas and Hidalgo. It seems best to recognize the 
common structural and geographical affinities of these species and we 
believe that Emery’s assignment of yogi to the subgenus Myrma- 
phaenus is the correct procedure. 
The meager biological data which we can present at this time are 
as tantalizing as the taxonomic history of yogi has been confusing. 
The type specimens were taken, according to Wheeler, “from a 
hollow twig of manzanita ... on Point Loma, near San Diego.” 
The senior author has examined considerable manzanita and live oak 
in coastal southern California without successfully relocating the 
species. Quite by accident the junior author was led to an examina- 
tion of the living stems of Haplopappus pinifolius (Gray) Hall. 
This shrub occurs in the foothill chaparral of the San Gabriel, 
San Bernardino and San Jacinto Mountains south to San Diego 
County. Although this species does not occur on Point Loma (the 
type locality of yogi), a related species, H. polmeri (Gray) Hall, is 
found there. It is possibly significant that all the records of yogi 
thus far are from areas where one or the other of these species of 
Haplopappus is known to occur. 
To date, the junior author has taken six colonies of yogi, all from 
stems of H. pinifolius. The most unusual point of this association 
is that all six colonies were taken from living stems. Numerous 
dead stems were examined, but only traces of former occupancy by 
yogi were found in these. So far as is known the ant does no excava- 
tion of the living tissues; all galleries are merely appropriated bur- 
rowings of buprestid larvae, apparently of one or two species of 
Acmaeodera. The manner in which the founding queen initially 
gains entry into the beetle burrows is not known. 
Attempts to discover something of the foraging activities of yogi 
have so far been futile. No foraging individuals have been seen 
during the day or at night. However, observations on a captive 
Explanation of Plate 13 
Camponotus (Myrmaphaenus) yogi Wheeler. Fig. 1. Male. Fig. 2. Minor. 
Fig. 3. Major. Fig. 4. Female. All figures drawn to the same scale. 
