;^52 



of dead megaccphaJa, wliit-h had been carried out of the nests 

 by the snrvivors. These fatalities apparently always took 

 place during cool rainy nights, and the heaps of dead were 

 only found at the entrances of nests located in the furrows 

 between the cane rows. The indication is that the ants were 

 overtaken by a flood of water, while in a chilled condition, 

 otherwise we should expect dead in the nests on the ridges 

 as well as in the furrows. An experiment was tried of flood- 

 ing a nest for a brief period during the day, but apparently 

 no fatalities resulted, for as soon as the water su])sided the 

 workers began carrying tlie bi-ood to a drier location. 



Dr. Perkins (1913) mentions low-lying localities, along the 

 coast, which from exce?ssive dryness and other causes, the 

 PheidoJe is unal)le to occupy, at any rate permanently. A good 

 example of such a locality is to l)e found just beyond Koko 

 Head crater, here on Oahu. Going over into this valley, a 

 marked change in the insect-fauna is to be noted. While 

 inerjacepliaJa is the dominant ant on the Honolulu-side of the 

 crater, there is scarcely a trace of this species on the opposite 

 side, which is an extremely dry and windswept area. Several 

 other ants have, however, adapted themselves to these diffi- 

 cult conditions. Both Frciwlrpls loiifjirorjiis and the fire 

 ant (Solcnopsis gcniinald var. riifa) are there in abundance. 

 The first species favoring the region of coral sand, and tlie 

 second the alluvial soil, further back from the shore, in accord- 

 ance with its agricultural habits. 



It is interesting to recall that these are the same species, 

 recently exterminated by niegacephald in the vicinity of my 

 home, in Palolo Valley. They are certainly driven to the 

 "ends of the earth" in a region such as we find beyond 

 Koko Head. 



HABITS. 



In favorable regions, such as we find in any of our humid 

 valleys, P. megocephala is exceedingly abundant. These ants 

 make use of every stone for a roof, and the large cracks in the 

 volcanic soil, which form during the dry season, furnish theui 

 ready-uuule chambers to a consideral)le de])th. Xaturally, 

 heavy rains are unfavorable to tluMii in tliis spongy soil, and 



