INTRODUCTION Ixxxv 



All the Hawaiian species of both genera are true forest insects and most of them 

 may be seen in large numbers, where they occur, flying round ferns and bushes in 

 sunny places. The males are often much more numerous apparently than the females, 

 but this is due to the more retiringr habits of the latter, which, when thev have begun to 

 provision their nests, frequent dark, shady and damp places in search of their prey. 

 This consists of the endemic Limnobiidae or daddy longlegs, which live in such places. 

 On one occasion I saw a number of N^esoniimesa hawaiiensis endeavouring to catch 

 Fulgoroid leaf-hoppers, that were running on a small tree-trunk, but they were quite 

 unsuccessful in their attempts, the hoppers when pounced upon always hopping off in 

 safety. Although I have often watched females of these wasps returning with prey to 

 their burrows, it was always Tipulidae that they carried to the nest. Their burrows 

 are usually made in the ground and are often drilled down from beneath a stone, this no 

 doubt serving to keep the burrow sufficiently dry. Sometimes numbers form their 

 burrows close together and I have found such colonies of N^esoiniviesa and Deinomimesa 

 mixed, a favourable slope and soil attracting both alike. On a few occasions Nesomi- 

 viesa has been observed to form its nest in tree trunks, probably utilizing the boring of 

 coleopterous insects. 



The parasitic Chrysididae, which so often attack Pemphredonids in other countries, 

 are wanting in our fauna and, so far as is known, the Hawaiian Mimesae have no parasitic 

 enemies. On one occasion I took the male of Nesomimesa nitida from the stomach of 

 a thrush {^Phaeornis) on Lanai. The comparative scarcity of prey appears quite suffi- 

 cient to prevent their becoming more numerous than we find them, in fact one is rather 

 astonished that they can procure sufficient to become so common as they are. 



Excepting Nesomimesa nitida, which is found on each of the three adjoining islands 

 Maui, Molokai and Lanai, all the species of the genus and Deinot)iii)iesa are confined 

 each to a single island. The latter genus is at present unknown on Oahu, Molokai, 

 Lanai, but has two species on both Kauai and Hawaii. N^esomi?nesa has two species 

 on Kauai, and one on each of the other islands. 



Crabroxid.\e. — The Hawaiian Crabronidae are represented by 18 described 

 species, which I have distributed in five genera. All these forms appear to be closely 

 allied and, as it appears to me, might well be the descendants of one original immigrant 

 form, allied to Crabro vagus. To this latter there are closely allied species in China 

 and America, and for this reason the Hawaiian forms may be either Asiatic or American 

 in origin. The Australian forms are very different. Of the 18 species represented, 

 three represent each one a distinct genus, while another genus, N^esocrabro, contains four 

 species, so that the greater part of the known forms fall into one genus, Xenoci-abro, of 

 which the others appear to be simply derivatives, and it is to species of Xenocrabro that 

 the European Crabro vagiis is most nearly related. 



Unlike the other endemic fossorial Hymenoptera (^Nesomimesa and Deinomimesa) 



