INTRODUCTION clxxxix 



of Phaeogramnia also probably await discovery, their secretive habits causing them to 

 be easily overlooked. 



Sapromvzidae. — Of this family, only a single species of Sapromyza has been 

 found, and that only in the immediate neighbourhood of Honolulu, rendering it highly 

 probable that the species is introduced. 



PiOPHiLinAE. — Represented only by the introduced Piophila casei, the produce of 

 the cheese maggot. 



Ephydridae. — Of the three genera enumerated, one, Brachydeute7-a, is represented 

 by a single N. American species. The other two, Notiphila and Scatclla, have each 

 a species not yet known from outside the islands, but their claim to endemicity is 

 uncertain. We suspect, however, that this family does contain endemic species. 



Drosophilidae. — This family is a most important constituent of the Dipterous 

 fauna, with nearly fifty species enumerated. They are very unevenly divided between 

 three genera, Hypenomyia with one, Idiomyia with five, and Drosophila with the 

 remaining species. The two former are endemic, and Drosophila is represented by 

 an assemblage of species, exhibiting great diversity in structure and appearance, and 

 will, doubtless, hereafter be found capable of division into other genera. At present 

 these insects, many of which are obscure and minute forms, have been very imperfectly 

 collected. To make an approximately complete collection and thorough study of the 

 Hawaiian species would require the devotion of many years of special work. Not less 

 than 250 species must exist in the islands, and double that number may very probably 

 occur. Many of the species preserve very indifferently as dried specimens, and it is 

 necessary that material should be preserved in alcohol as well as pinned. Those found 

 in cool, wet forests often shrivel and distort, either soon after death, or when brought 

 down into the hot and comparatively dry climate of the lowlands. Some of the species 

 are quite conspicuous, and are readily attracted by the sap oozing from a broken limb 

 of a tree, or from exudations caused by decay or disease. Very many breed in stems 

 of trees or plants, which, when decaying, yield abundant moisture — such as those of 

 the arborescent lobelias, of bananas, tree-ferns, etc. The larvae abound also beneath 

 the bark of some forest-trees, which, when this is stripped off, reveal a semiliquid or 

 pulp-like material covering the wood. Some of the larger and very many of the 

 smallest and most obscure species live amongst the soft ferns, which grow in damp 

 places beneath the shade of the forest-trees. The larvae of these flies are very subject 

 to the attacks of Hymenopterous parasites, Proctotrypcs kawaiiensis, and species of 

 Phaenopria (Proctotrupoidea), several of the Eucoilinae (Cynipoidea) and Spalangia 

 lanaiensis (Chalcidoidea) having been bred from them. The common Crabronid wasp, 

 Hylocrabro tiimidoventris, often fills its cells entirely with species of DrosopJiila, but the 

 one which it most usually carries off is, I suspect, an introduced one. 



