I. HYMENOPTERA ACULEATA\ *'"'•' a"- 



§ 1. General considerations on the Aculeata. 



The Aculeate Hymenoptera of the Hawaiian Islands form an important part of 

 the fauna, nearly 200 species being at present known. Each of the large divisions 

 of the group, excepting the Heterogyna or Ants, is represented by many endemic 

 species. The Fossores include 34 species, divided between four sub-families ; the 

 Diploptera are well represented by 88 species in two sub-families, the Anthophila or 

 bees by 56 species in three sub-families. The total number of species in these 

 groups as represented in the islands, is therefore 1 78, but of these some are known 

 to have been introduced in recent times from other countries, while others from 

 various kinds of evidence we can be tolerably certain are also to be regarded as 

 having been imported by man. To arrive at a true understanding of the peculiarities 

 of the fauna, it is necessary to consider each family in detail. 



i. In the Fossores the Sphegidae are represented by a single species of Pelopceiis, 

 an American insect, known to have been introduced. 



The Trypoxylonidae have two species of the genus Pison. Although both of 

 these were described from the islands yet one of them is also known to inhabit 

 Fiji. It is an abundant species, generally being found about houses, and nests in 

 the woodwork of which these are built, and is never found at any great distance 

 from towns or settlements. The second species was found only in Honolulu some 

 twenty years since. There is little doubt that both these species are importations, 

 and I suspect that P. iridipennis after arrival has failed to establish itself. 



The Mimesidae have 10 species divided equally between two genera, both of 

 which are endemic. The two genera are certainly allied, and have probably arisen 

 by divergence from a common ancestor, and evolved species side by side, the one 

 not being a direct off-shoot of the other. 



The Crabronidae are represented by 21 species in two genera, of which one 

 containing 6 species is endemic, as also are all of the 21 species. It is probable 

 however that the 15 endemic species now referred to the sub-genus Solenius of 



' By R. C. L. Perkins; except Heterogyna (or Ants): this is by Prof. Aug. Forel of Ziiricli. 

 Hymenoptera Parasitica has been undertaken by Dr L. O. Howard and Mr Ashmead, of Washington. 

 There are no Hymenoptera Sessiliventres in this Fauna. 



P. F. H. I 



