cxxiv FAUNA HAWAIIENSIS 



species of Xyleborns two of the most abundant, A', confusus and X. ptibescens, are 

 introductions by man, and one or two of the other species are very Hkely to prove to 

 be foreign. X. pubescetis {immaiurus Bl.) is an injurious species, attacking trees that are 

 temporarily unhealthy, and in that case sometimes causing their death, when otherwise 

 they would no doubt recover. It may be seen in vast numbers breeding in trees that 

 are scorched by forest fires, and is sometimes common in the city of Honolulu. It has 

 also been introduced into Queensland, where it was observed in myriads in felled timber 

 in one locality, and no doubt it will become ubiquitous throughout warm countries, 

 wherever the climate is suitable. The native species are very difficult to distinguish 

 from one another, and there is great sexual dimorphism, so that it is not possible to 

 associate the sexes in the present state of our knowledge. The males are usually much 

 rarer than the females, and large colonies of the latter may be found without a single 

 example of the former sex. One group of large-sized species is attached to the tree 

 Cheirodendi'on. Others attack Acacia koa, Piptjirus and other trees, while the intro- 

 duced species are partial to Aleurites triloba, the apodemic 'Kukui' tree. For most 

 of the endemic species a tree has to be in a particular condition of decay or disease in 

 order to be attacked. The species of Hypothenenms are, doubtless, all introduced. 

 H. eruditus is sometimes found in the covers of books, as in other countries, but it 

 also breeds very freely in the open, in dry stems of many plants, and in the twigs of 

 many bushes and trees. It is parasitized by a minute Bethylid, probably a Cephalonoiiiia. 

 H. insularis and H. ruficeps, described by me, are varieties, I believe, of this variable 

 species. H . viaculicollis is often found with H. eruditus and is very common in twigs 

 of tamarind. Hibiscus, and many other trees and plants. It is also fond of boring in 

 the trunks of large avocado pears [Persea) when these are not quite healthy, and 

 aggravates their condition. Crossotarsns externedentatus sometimes joins in the attack 

 on this tree and becomes very numerous. The species of Hypothenenms are mostly 

 confined to the lowlands or lower elevations rarely attaining an elevation of 2000 ft. in 

 the mountains. 



Anthribidae. — Represented by only foreign forms, unless, as is improbable, 

 Araeocerus constans, which is very closely allied to the introduced A. fasciculatus, should 

 prove to be endemic. It is very common in the Kona district of Hawaii, frequenting 

 the flowers oi Argemone mexicana. A. fasciculatus is one of the commonest of beetles, 

 breeding in immense quantities in the fruits or seeds of many native and foreign trees, 

 and also in dead wood, dry stems of sugar cane etc. It is occasionally parasitized by 

 an Etipelmus. It ranges from the coast, throughout the mountain forests of all the 

 islands. Of recent years two or three exotic Anthribids have become imported and 

 established. These belong to the common tropical genera that have the antennae 

 greatly elongated. One of them we have found swarming in consignments of coconut 

 drupes imported for seed. 



