INTRODUCTION cxxiii 



The lo species of the genus Heieraniphus are of great interest. They seem to 

 be best represented on Oahu, which yields five of the known forms. H.filiciim is 

 common in decayed parts of the stems of tree-ferns in the mountains near Honolulu. 

 It exhibits a good deal of variation, and different colonies apparently sometimes differ 

 considerably in appearance. H. zvollastoni, foveatus and cylindricus are all common 

 on the liliaceous plant, Astelia ; sometimes all are found in company on a single plant, 

 sometimes two of the species are mixed, sometimes only one occurs. On one occasion 

 a single plant yielded not only these, but H. hirtelbis as well ! It is very remarkable 

 to find all these species living absolutely together, and with perfectly distinct specific 

 characters, when we must suppose, that all originally were the product of a single form. 

 In spite of apparently an identical mode of life, species formation of the most distinct 

 kind has taken place. Of the four species, H. cylindricus exhibits much variation, 

 the others are much more constant. H. haleakalae and H. frater are found beneath 

 rotting logs in the same locality and may not be distinct species ; kaiiaiensis has the 

 same habit, and violokaiensis was found in wet moss on tree-trunks. 



Oodenias is a remarkable endemic genus with 48 described species, with others 

 known, but undescribed. The species are extremely difficult, many of them being 

 variable, while some exhibit marked sexual differences and others little or none. The 

 larvae of all feed on dead wood or ferns, excepting borrei, which is common beneath 

 stones, where only a scanty vegetation of grass-tufts and a few low plants exist. 

 O. brunnetmi is found in dry frond-stalks oi Pteris. Many of the species, like O. aenescens, 

 are polyphagous, attacking the dead wood of many kinds of trees. In fact this species 

 and some others are even found in stems of low plants. Others, however, are either 

 solely attached to one sort of tree, or, at least, are rarely found on more than one. 

 Some of the species, e.g. O. corticis, O. nivicola and O. midtiforvie, are very numerous 

 in individuals and many of the species are gregarious, so that a number of examples 

 may be found in proximity. Many, however, are difficult to collect and are still very 

 imperfectly known. No parasites of these beetles are at present known, but they are 

 a favourite — perhaps the favourite — food of several species of the remarkable birds of 

 the genus Heterorhynchus, and the allied Hemignathus also devours large numbers of 

 them. 



A^wtheorus with three species is allied to the preceding. A. montanus breeds in 

 the dead wood of Aleurites, Acacia koa, Pisotiia etc. in the mountains just behind 

 Honolulu and elsewhere on Oahu. It appears to have become very much more abundant 

 of late years than was formerly the case. Once difficult to obtain, it is now a common 

 beetle, and is sometimes found in company with the introduced Pseudolus hospes and 

 Dryopkthorus distinguendus. 



ScoLYTiDAE. — Three genera with 24 species are considered in this work, but one 

 or two other genera are now represented by recently imported species. Of the 19 



q2 



