532 
JOURNAL OF ECONOMIC ENTOMOLOGY 
[Vol. 16 
Nearly all of our pests are immigrant species, and many of them have 
become established in Hawaii without the checks upon their multi¬ 
plication which exist in the lands from whence they came. The climate 
here also is conducive to the rapid multiplication of insects. The 
temperature rarely falls below 60 degrees Fahrenheit in the lowlands. 
Hence, it is possible for the development of insects to go on without 
interruption, and six to eight cycles annually is not unusual for many 
species. Hibernation phenomena are scarcely discernible. Again, a 
luxuriant vegetable growth furnishes an ample supply of good. 
In these circumstances, adaptable species reach excessive numbers in a 
very short time, occupy the land to the extent of available food, and 
generally become a scourge on improved land. Artificial methods of 
control are inadequate to the situation, usually not giving the desired 
results and involving excessive expenditure to get even poor results. 
On the other hand, all the conditions cited as favorable to the ex¬ 
cessive multiplication and rapid dissemination of injurious forms, like¬ 
wise favor the use of natural agencies for their restraint. The intro¬ 
duction of beneficial insects can be undertaken at any time of the year, 
their propagation and colonization are greatly facilitated by the abun¬ 
dance of host material and the absence of a dormant season, which in 
more northern latitudes often seriously hampers biological work. The 
peculiar nature of our insular fauna is also a favorable circumstance here, 
the paucity of forms operating to make the incidence of hyperparasitism 
less likely. 
Finally, the character of our agriculture is also a favorable circum¬ 
stance. I mean to say that the bulk of our production is limited to a 
comparatively few crops, grown under field conditions over large areas, 
and the business of production is highly organized. These features all 
work advantageously. In the first place, the limited scope of the work 
makes it a possibility as far as the time element is concerned. Secondly, 
centralized management and adequate support are essential to expensive 
work involving a high degree of technical skill and sustained effort. 
Thirdly, the effect of a small improvement is rendered disproportionately 
great when the application of it is extensive. 
In stating that our work along the lines of biological control has been 
successful, I do not wish to be understood to imply that the success has 
a 
been uniform in degree or that the establishment of a beneficial species 
has succeeded from every introduction made. Quite the contrary has 
been the case. The consignments received from our collectors which 
have produced results are few in number when compared with the total 
