315 



dry ends of the lower spurs of the mountains, in the sides 

 of the gulches, in the marshes, along the sea shore and in 

 some of the more arid regions where the lack of surface water 

 cheeked the wanderings of the cattle. 



The endemic insects, being as a rule but little adaptable 

 to new host plants, receded with- the plants to which thev 

 were attached. 



With the spread of cultivation and the introduction of 

 hundreds of species of plants for economic purposes or for 

 ornamental plantings for many years entirely without any 

 system of port examination and quarantine, many insects at- 

 tached to these plants w^ere introduced and became established. 

 Some of these entered into direct competition with endemic 

 lowland insects. Other insects, however, which were para- 

 sitic and predaeeous upon the introduced insects soon 

 adapted themselves to attack the endemic lowland insects and 

 reduced their numbers. Among these one species is doubt- 

 less more important than all the rest. The ant, Pheidole 

 megacepliala, is eminently predaeeous in its habits, attacking 

 other insects indiscriminately and wherever it has spread 

 the endemic insect fauna has practically disappeared, only a 

 few Hymenoptera, such as species of Crabro, Odynenis and 

 Nesoprosopis, some Coccidae, Jassidae, and Delphacidae among 

 the Homoptera, some ITeteroptera, some Lepidoptera and pos- 

 sibly some Diptera have been able to survive where this ant 

 is able to maintain itself in its full numbers. But none of 

 the characteristic groups of endemic Coleoptera are alile to 

 persist where it is found since they are generally sluggish, 

 of feeble powers of flight, and defenseless against the attacks 

 of the myriads of ants present in the cultivated area of the 

 islands. 



It has been generally recognized that the cooler and 

 generally damper climate of the mountains forms an im- 

 passable barrier to the spread of Pheidole, but it is not so 

 well known that there are certain of the dryer areas of the 

 lowlr.nds in which it is unable to maintain itself. Since these 



