INTRODUCTION clix 



caterpillars are now greatly attacked by Bracon omiodivor'uni (an introduced species) 

 and the Ophionine Linmeriuvi blackburni, sometimes also by a species of Enicospilus in 

 the latter group. The two common Tachinid flies, Chaetogaedia monticola and Frontina 

 cxrchippivora, also parasitize the caterpillars. The Pimpline Ichneumons, Eckthromorpha 

 maailipennis and Pimpla hawaiiensis, as well as the very abundant, imported Chalets 

 obscurata, are bred from the pupae. From one of the forest-frequenting species (C. asa- 

 phoiiibni) Swezey has bred the Bethylid, Siero/a diclwoiiia, and it is likely that others of 

 this genus will attack other Oniiodes larvae. In addition to these parasites, various 

 species of Odynerus carry off the caterpillars to store their cells. Odynerus nigripennis 

 is a constant enemy of Omiodes accepta and other grass-eating species, as well as of the 

 leguminiphagous O. vionogona. The rarer wasp Odynerus cpipseitstes has been noticed 

 hunting for the caterpillars of Omiodes continuatalis. The imported social wasps of the 

 genus Polistes also use those of various species, as food for their young, while various 

 other polyphagous predators feed on them when opportunity offers. 



The species of Phlyctaenia are numerous, twenty-six having been already described, 

 while others have since been discovered. In their larval habits they much resemble 

 Omiodes, and some of them are amongst the most abundant of moths. They differ, 

 however, in the fact that the caterpillars are entirely or almost entirely attached to 

 dicotyledonous plants for their food supply, though I have some suspicion that the 

 Omiodes-like P. heterodoxa will be found to live on SisyrincJiiuvi or some other mono- 

 cotyledon. In the forest region of the islands many trees or shrubs are attacked by 

 the caterpillars of Phlyctaenia. Some species attack very different food-plants, e.g. the 

 common P. despecta, which is extremely abundant on Ipomoea and various composite 

 plants and occupies with equal success stations near the driest coasts or high up the 

 mountains, where it can thrive in the wettest forests. Such species exhibit considerable 

 variation as is natural, but it is not clear to what extent this is due to climate and to 

 what extent to food-plant. Some of the species, e.g. P. monticolans and eucrena, vary 

 greatly even when taken in the same station. Many of these moths are easily disturbed 

 in the daytime, as one walks along, or are even on the wing naturally. P. pyranthes 

 sometimes flies freely in the sunshine in open places in forests amongst Vaccinium 

 reficidatum, on which the caterpillar feeds, being much more abundant than the moth. 

 Like all the other members of the genus this day-flying species flies also by night and is 

 attracted by light. P. calliastra was noted as flying freely at the approach of darkness, 

 soon after sundown, then remaining quiescent till midnight or later, the period of 

 activity of this, as of other species, being evidently very short. P. micacea may be 

 noticed flying from tree to tree in wet forests, growing on rough lava flows, and settling 

 on the mossy tree trunks. When at rest it raises the abdomen and has in consequence 

 a peculiar appearance. 



The natural enemies of Phlyctaenia are much the same as those of Omiodes, and in 

 addition to these, P. despecta is attacked by the Braconid Chelonus blackburni. Probably 



