22 
Psyche 
[March 
getting the ants to move into the brood chambers of a 
small plaster-of-paris Janet nest. The workers had soon 
massed the brood and were back out foraging in the food 
chamber. 
During the next several days the following small animals 
were introduced alive into the food chamber: nematodes 
(possibly confused with small enchytraeid annelids), mites, 
spiders, isopods, millipedes, symphylans, entomobryid and 
onychiurid collembolans, campodeids, homopteran and he- 
teropteran nymphs, fly larvae, beetle larvae and adults, 
and an adult minor worker of the ant genus Pheidole. 
The Rhopalothrix showed definitely neutral or aversive 
behavior toward the isopods, millipedes, onychiurid col- 
lembolans, beetle adults, and Pheidole. The nematodes, 
mites, and homopteran nymphs were completely over- 
looked or at least no definite reaction was recorded. One 
worker seized a cyclorrhaphan fly larva but was not able 
to subdue it. The remaining prey offered — spiders, sym- 
phylans, entomobryid collembolans, campodeids, and he- 
teropteran nymphs — were captured and then eaten by 
the workers or larvae or both. Of this last group, entomo- 
bryids were the most quickly captured, and this could 
be explained on the basis of their relatively small size 
and feeble strength. My observations are too limited to 
establish prey specificity within the accepted group, but 
I believe that entomobryids may have formed the principal 
dietary staple of the colony in nature, since these insects 
were far and away the most abundant and accessible 
arthropods in the vicinity of the nest. Otherwise, if any 
generalization is to be made about food preference, it is 
probably safest to say that this species of Rhopalothrix 
accepts a wide variety of soft-bodied arthropods and 
rejects other animals that are either hard-bodied or possess 
repugnant odors. 
Hunting behavior of the observation colony was very 
similar to that we have seen in the short-mandibulate 
dacetines. The workers foraged with the same slow, de- 
liberate gait, but in addition punctuated by little total 
halts in the movement, one to three a second, making 
them appear to jerk along. On contacting potential prey 
