INTRODUCTION cxlvii 



is one of the commonest species, and its caterpillar sometimes does much damage to 

 farm produce, stripping the potato, tomato and many other plants of their foliage, as 

 well as gnawing through the stems. In this work it is frequently aided by the cater- 

 pillar of the very dissimilar moth A. crinigera, both being truly 'cut-worms' and in the 

 larval state remarkably similar to one another. Sometimes one and sometimes the 

 other is the most injurious, but dislocata appears to thrive at higher altitudes in the 

 mountains. On the uplands of Hawaii, as at Waimea, where A. dislocata sometimes 

 does much injury to cultivated plants, the moths are noticeably different from those 

 taken on Oahu, Molokai, etc. They are greyer or whiter in appearance and this gives 

 them a distinctive look, when series of examples are placed side by side. These two 

 injurious species are a favourite food of the golden plover, which catches the moths, 

 as well as their caterpillars. 



On the high mountains above the forest-line and in open forest A. crinigera seems 

 to be replaced by allied forms, A. mesotoxa, epicrenina and baliopa, which never descend 

 to the open country below the forest. Similarly, at great elevations, A. dislocata is 

 replaced by A. aulacias on Maui and on Hawaii by an undescribed species. 



At present little is known as to the parasites of Agrotis and Leucania, except that 

 some of the species are much destroyed by the Tachinid Chaetogaedia monticola and to 

 a lesser e.xtent by Frontina archippivora. 



A species of Enicospilus has been bred from A. dislocata, and it is therefore likely 

 that the Ophioninae will be found to attack many of these caterpillars, as they are 

 partial to the endemic Leucaniae. 



All the endemic Agrotis have great powers of th'ght, and many of them rise so 

 readily in the daytime, as one walks along, and travel at such speed with the wind, that 

 even where individuals are very numerous, it is often difficult to capture many specimens. 

 This is especially the case with those that frequent the open and exposed parts of the 

 higher mountains, where strong winds are prevalent. Many of the species are very 

 strongly attracted by the juices exuding from decaying fern leaves, and also by artificial 

 lieht, while some visit the flowers of Metrosiderus and sandal trees, and no doubt others. 



Heliothis ai-miger, though a common insect, does not appear ever to attain here the 

 extraordinary abundance that it reaches in other countries. The larvae, often lying 

 exposed in the flowers of Sida, or on other plants, are very subject to the attacks of the 

 two Tachinid flies mentioned above, as being parasites of Agrotis, and in some seasons 

 nearly all the specimens found are parasitized. The colour variations of the moth are 

 numerous, and are not of local occurrence. Thus eight examples taken together on 

 Molokai varied from the palest yellow form to the darkest suffused one, not two indi- 

 viduals being alike. On the dry lowlands H. ariniger is rare, except during the winter 

 months, or when Sida and other lowland plants spring up afresh after heavy rains. 



The two species of Spodoptera are doubtless natural immigrants, 5. exigua being 

 practically cosmopolitan in warm regions, while S. mauritia is one of the few insects 



t2 



