194 
Psyche 
[September 
colony suggest that this species regularly forages at night. During 
the day, members of the captive colony normally remained crowded 
within galleries cut into a wood block; with the coming of darkness 
they moved out of the tunnels to the surface of the block to feed 
on a honey-water solution provided for them. 
The captive colony showed no interest in dead insects nor in 
various vegetable foods (seeds, bran, wheat germ, pollen, etc.). The 
primary food source seems to be the sweet exudates of several species 
of Pseudococcidae. Species of mealybugs are: Puto sp. 4 , (immatures 
only), Humococcus inornatus McKenzie 5 , Anisococcus crawii 
(Coquillett ) 5 and Chorizo coccus abroniae McKenzie? 5 . The first 
two species were taken from the galleries occupied by the ant, and 
were feeding on the plant within these galleries. In the case of the 
two latter species there is some confusion, since both were mixed in 
a single vial; some of the specimens are known to have come from 
the galleries while others were taken feeding on the outer surface of 
the stems and crowns. Whether or not the ants actually moved the 
mealybugs into the galleries remains to be determined. However, 
that ants do transport mealybugs to advantageous feeding sites is 
well known, and it would not be amiss to suggest that yogi does so. 
Two ant species have been found living in a plesiobiotic relationship 
with yogi . There are Solenopsis ( D .) rnolesta validiuscula Emery 
and Leptothorax andrei Emery. Each of these was found only once, 
and little can be said here regarding their relationship with yogi. 
The former species is commonly associated with larger ants, and the 
latter has been taken several times from colonies of various species 
of Camponotus and Formica. 
One colony was apparently being attacked at the time it was 
collected. The attacker was Formica (F.) pilicornis Emery, a com- 
mon and aggressive species in the lower chaparral region. The 
Formica had gained entrance into the galleries of the Camponotus , 
and workers of the former were seen carrying off the larvae and 
pupae of yogi. The remainder of the yogi colony, soldiers, workers, 
the queen and some brood, were crammed into three upper galleries, 
the majors lowest and receiving the brunt of the attack. The majors 
of yogi were massed together, with antennae extended forward ; when 
a pilicornis worker touched the antennae the yogi major lurched 
forward and attempted to fasten its jaws to an appendage of the 
attacker. Several such encounters were noted; when the defender’s 
Metermined by H. L. McKenzie 
determined by R. F. Wilkey 
