cxxvi FAUNA HAWAIIENSIS 



joints, the shape of the pronotum and the development of the humeral angles of the 

 elytra. As all these characters have to be used for the differentiation of the species, 

 it may readily be understood, that years of study may be necessary before a satisfactory 

 elucidation is attained. With regard to the variation in the individuals of the colonies 

 mentioned above, it is worthy of note that we have found in the case of some species 

 that whereas the individuals of one colony exhibit no variation of note, in another colony 

 may be found examples so variable that, had the extreme forms been found apart, one 

 would have hesitated to consider them as belonging to a single species. Whether this 

 is due to the mating of similar parents in the one case and of dissimilar ones in the 

 other can only be settled by experimental breeding in the homes of the insects. They 

 do not thrive if removed from the forests, and may even be affected in superficial 

 characters, when bred on the lowlands. Thus a series of P. vestitus reared in Honolulu 

 could not be matched in colour by any of many specimens gathered from the very same 

 trees at an elevation of about 2000 ft. in the mountains. 



Oedemeridae. — Oxacis collaris described from the islands, is certainly an importa- 

 tion and has often been seen in great numbers on foreign trees and shrubs about the 

 town of Honolulu, and of recent years has spread throughout the island of Oahu. 

 Doubtless, it will reach the other islands, if it has not already done so ; sometimes it is 

 extremely abundant at light. It sometimes visits certain flowers in the daytime, and at 

 a time when many of the shrubs in Honolulu were covered with the Coccid, Ceroplastes 

 rubens, it literally swarmed over the foliage, probably attracted by the excreted honey- 

 dew. Quite recently one, if not two other Oedemerids have been imported into the 

 islands, but have not yet become generally abundant. 



AxTHiciDAE. — The two species of Anthicus, which frequent the neighbourhood of 

 the coast may be natural immigrants, being widely distributed in the islands, and one of 

 them, at least, is very abundant. A. oceanicus has been recorded from the Marquesas. 



CiSTELiDAE. — The genus Cistela contains seven described endemic species, and 

 Labetis with five is supposed to be endemic. The species of Cistela are closely allied 

 and difficult to determine and as a rule not numerous in individuals, so that they have 

 been imperfectly studied. They appear to be diurnal as they are found on the foliage 

 of trees and on ferns in the daytime and occasionally are seen on the wing, as is the 

 case with the Labetis of Kauai. The species of the latter genus that occurs on Hawaii, 

 however, is nearly always found resting beneath the bark of Acacia koa in the daytime, 

 several examples being sometimes found in company and we do not remember seeing it 

 active in sunshine like the others. The species are extremely closely allied and the 

 larvae are not at present certainly known, but Tenebrionid-like larvae, superficially 

 somewhat similar to those of some Eucnemidae and found with these are probably to 

 be referred to the Cistelidae. 



