clxxx FAUNA HAWAIIENSIS 



The endemicity of the less easily collected Hemerobiidae cannot be properly 

 estimated till much larger collections are made ; but in its Chrysopinae there is no doubt 

 that the island of Hawaii is disproportionately rich. It is now well-known that some 

 species originally recorded from a single island are by no means confined to one, but 

 range over two or several. 



Review of Diptera. 



The Diptera (excluding the Pupipara) are represented by 26 families, 10 of which, 

 I believe, contain endemic species, and 13 only imported ones, the families Ephydridae 

 and Agromyzidae being doubtfully represented by endemic forms. Excluding these 

 latter, the native fauna belongs to the Mycetophilidae, Chironomidae, Limnobiidae, 

 Dolichopodidae, Pipunculidae, Sarcophagidae, Anthomyidae, Trypetidae, Drosophilidae, 

 Asteidae. In addition to these the Pupipara are represented by three species of 

 Olfersia (Hippoboscidae), one of which is described from the islands, the other two are 

 known elsewhere. Though found on the native Passerine birds, they also occur on 

 wide-ranging sea-birds, and can only be considered as immigrant species. Excepting 

 perhaps some of the metallic-coloured Sarcophagidae and a few of the largest Droso- 

 philidae, the endemic flies are all of small size and of the most obscure superficial 

 appearance. They have only been specially collected to a small extent and the number 

 of those described can be but a fraction of those that exist. The extraordinary develop- 

 ment of the Drosophilidae, in structure and in the number of species, is the most 

 striking feature of the Dipterous fauna. The number of described endemic species of 

 Diptera is only 135, while the introduced ones number 57. The former are contained 

 in 27 genera, the latter in no less than 46. 



Mycetophilidae. — This family is probably represented by endemic species of 

 Sciara and Platyiira, and as its members have been little collected other species and 

 even genera are likely to be found. If preserved as dried specimens, these insects are 

 subject to much distortion after death and often become hardly recognizable. It Is prob- 

 able that the truly endemic forms are numerous, the larvae being very plentiful in 

 decaying vegetation, where they are preyed upon by the small Carabid beetles, and, if 

 they have been exposed, are also seized upon by minute carnivorous flies belonging to 

 the Dolichopodidae. A number of species have been imported with foreign plants and 

 have become very abundant, so that it may not be very easy to discriminate the foreign 

 from the native species in these obscure flies. 



Chironomidae. — Chirononms Hawaiiensis is one of the commonest of insects, 

 especially near the coast or on the lowlands. Its status as a native insect is very doubtful. 

 Being freely attracted to light, it often swarms in the verandahs of houses, and forms a 



