8 
BULLETIN 965, IT. S. DEPARTMENT OF AGRICULTURE. 
wherever it has become established. Only on the margins of the 
Argentine ant infestations does one find colonies of the native Pre- 
Fig. 4.— Characteristic trails of the Argentine ant on a tree trunk. 
nolepis, Formica, and others. They have repeatedly been observed 
to dislodge the large red agricultural ant (Pogonomyrmex californicus 
Buckley) from its nest, though sometimes this species persists for a 
