INTRODUCTION cv 



occurs, but is rarely noticed amongst the swarms of its economically important congener. 

 C. polynesiale, though occurring in Blackburn's period of collecting, is almost sure to 

 prove an introduction, and recently a third species (though of another genus, Hockeria) 

 has become perfectly naturalized on Oahu. Chalcis obscurata is interesting, otherwise 

 than economically, owing to the fact that it frequently attacks insects already parasitized 

 by some other insect. Consequently it has even been bred from the pupa of other 

 parasitic Hymenoptera (e.g. the Ichneumonid Echtlii^omorpha niaculipeniiis) and Tachinid 

 riies. It seems deficient in its instincts, for we have observed one ovipositing in the 

 pupa (concealed of course between the layers of palm leaf) of Oniiodcs blackburni, when 

 examination showed that the pupa had previously been squashed flat, and was quite 

 dead and dry. Nevertheless in productiveness it is one of the most successful of insects. 

 Epitramis /acteipeitnis^.discov&'CG.A by Mr Blackburn, still occurs on Oahu, but is rarely 

 met with. Its habits are not known, nor has it been found except in the neighbourhood 

 of Honolulu. 



EuRYTOMiDAE. — Represented only by species of Eurytoina and one or two of 

 Isoso77za, all of recent introduction. The former is hyperparasitic, attacking Braconids, 

 especially Bracon omiodivonis, a common parasite of Pyralid caterpillars, and less 

 frequently Apanteles. Its presence was not noted until 1903, when it was already 

 numerous. It is very widely distributed, and in Honolulu we have found it on the dry 

 coast of Waikiki, as a hyperparasite of Omiodes blackburni, as also in the wet valley of 

 Nuuanu. It is common in some of the cane-fields of Hawaii, where Omiodes accepta 

 is an abundant host of Bracon, and on one occasion at Pahala we observed countless 

 numbers of the males flying round and running on the leaves of cucurbitaceous plants, 

 growing in waste places. The 'joint-worms' or larvae of species of Isosoma are 

 attached entirely to imported grasses, and are abundant in Honolulu and no doubt 

 elsewhere. There appear to be two species, which are parasitized by an Eupelmine 

 Encyrtid, and I think also by a Pteromalid. 



MiscoGASTERiDAE. — This family is chiefly represented by a number of species of 

 Toxeuma all endemic, and by the endemic genera Neolelaps and Mesolelaps, the former 

 with several species, though only two have been described. These are all true forest 

 insects and usually sparingly met with. Though we have bred one or two species, 

 their habits are not certainly known. They appear to be associated with the caterpillars 

 of microlepidoptera or small beetles that attack stems or fruits of native trees. The 

 species of Toxeuma are likely to prove very difficult to distinguish. They are bred 

 from twigs containing small beetle larvae, Proterhinus, Cis, etc. 



Encyrtidae. — The sub-family Eupelminae is chiefly represented by about fifty 

 described species of the ubiquitous genus Eupehmis, forming a remarkable series, diverse 

 in structure and in habits. The specific value of a good many of those that I have 

 F. H. I. 



