clxxxiv FAUNA HAWAIIENSIS 



of the species of these flies are confined to the forests, but some stray below its limits 

 and some above. Some are found in plenty, and individuals are to be seen constantly 

 passing by on the wing, flying from plant to plant, the males in search of the females, 

 the latter more carefully scrutinizing frond, leaf, or branch, in search of their hosts. 

 Occasionally a pair are seen hovering in the air in copula, the larger male sustaining 

 the female. As in other countries, the size of the fly, when bred, often appears very 

 large as compared with the body of its host. So small a leaf-hopper as Nesosydne 

 raillardiae will produce a comparatively large Pipunculus. The puparia, so far as is 

 known, are always formed on or beneath the soil. They are never found exposed and 

 attached to the surface of leaves as is the case elsewhere with certain (but probably few) 

 species. 



Syrphidae. — This important family is quite unrepresented by endemic forms and 

 the few introduced species, excepting perhaps Xanthogramma grandicorne, a common 

 Australian insect, are of quite recent importation. Volucella obesa, Eristalis pundulatus, 

 Syritta oceanica and Eumerus marginatus have all become established during the years 

 of my residence in the islands and all are now very common insects. The Volucella 

 was first seen in 1894, while the others appeared between 1897 and 1900. Eristalis 

 tenaxvj2£, already common in 1892. It thrives best at high elevations in the mountains. 

 The Xanthogramma is a very beneficial insect, but is unfortunately much parasitized 

 by the ubiquitous Ichneumonid, Bassus laetatorius, and sometimes by a species of 

 Pachyneuron, unless this latter proves to be parasitic on the Basstis. The Syritta 

 breeds in decaying vegetable matter, and has been reared from pots containing plants, 

 the soil of which had been mixed with horse or cow droppings. 



Oestridae. — Represented only by three species, imported with domestic animals. 

 These are Oestrus avis, Hypodernia bovis and H. nasalis. 



Tachinidae. — Represented by only three or four species, probably all foreign and 

 most likely importations by man. A small unidentified littoral species might possibly 

 prove to be endemic. Frontina archippivora is an extremely common fly, parasitizing 

 Anosia and Pyj'ameis cardui, as well as the caterpillars of many moths of various 

 families. It is of great economic value and is said to have been imported from America 

 by Koebele. It is known to be of recent introduction. Chaetogaedia nionticola is 

 another very beneficial species, which attacks many of the most injurious caterpillars. 

 Its habits have been studied by Swezey, and are of some interest, owing to the fact 

 that it is one of those which deposit their eggs on the leaves of plants, instead of on a 

 living caterpillar. It is of course largely a matter of chance whether the &gg is 

 swallowed by the latter, and hence the female fly is very prolific and the eggs minute. 

 This Chaetogaedia may be a natural immigrant ; at any rate it was universal throughout 



