cxxxviii FAUNA HAWAIIENSIS 



interest. There are two species of Atheta, one imported, the other possibly so, though 

 not known elsewhere. The species of Phloeopara, Xenusa and Stenagria are not likely 

 to be endemic and are very probably importations. 



The native Myllaena, Oligota and Diestota all exhibit much variety in their habits, 

 but species of all of them are found in decaying trees beneath the bark, and we have 

 found all together in a single tree Lobelia. Some of the species of Myllaena only 

 occur under stones, especially on the edge of streams, others are found in the flowers 

 of Freycinetia or Lobeliaceae with Diestota, Nitidulidae, etc. Some are only found 

 beneath large decaying logs. The Oligotae besides occurring under bark of various 

 trees are some of them specially attached to the foliage of plants, e.g. trees of the 

 composite genus Dubautia. Liophaena appears to be partial to dry, or moderately dry, 

 dead branches of trees especially Acacia koa. 



There are a good many common species amongst the three large genera above 

 mentioned, but they require special collecting and the very minute Oligotae are easily 

 lost, unless a special bottle is carried for their reception. I have no doubt that I lost 

 many individuals that I came across in general collecting. Some appear to be always 

 found singly or one or two together, while some living beneath bark form little colonies. 

 I once found a score or more of a brightly metallic species beneath a small piece of bark 

 of Acacia koa on Kauai, but these must have been lost, as the species is not amongst 

 those described. It is probable that the species of Myllaena found beneath logs and on 

 the ground are flightless, excepting those that frequent the margins of the running 

 streams and are very active. 



Hydrophilidae. — It is doubtful whether any of the few known representatives of 

 this family are really native, though the genus Oniicrus was described from the islands, 

 and Hydrobius nesiticus and seniicylindriciis also are riot known elsewhere. It is note- 

 worthy that two of these species have only occurred on Oahu. Cyclonotuvi extraneum is 

 certainly an imported species. The two species of Dactylosternwn are also, doubtless, 

 importations. The species of Hydrobius are of interest from the fact that the fresh- 

 water fauna of the islands is so very scanty. 



H. semicylindricus is a very abundant beetle and I think is sure to be found 

 elsewhere. The fact that it has been found in artificial water-containers led to the 

 suspicion that it was an importation by man, but the occurrence of a second species, far 

 in the native forests, renders it possible that it is a natural immigrant. 



Dytiscidae. — A single species of Rhantus and one of Colyinbetes are ubiquitous in 

 the mountain streams. Both exhibit variability and it is doubtful whether they are 

 natural immigrants or whether they are really endemic. On the whole the former is 

 the more probable ; a closely allied species of Rhantus is found in the far distant island 

 of Tahiti. 



