1894.1 55 



uumbers, and is now very plentiful on the windows in dwellings, and 

 on flowers and shrubs in gardens at Ashburton. Six weeks ago I wrote 

 to a friend residing in Oamaru, requesting him to collect a number of 

 flies for me that he probably would observe in his house and garden. 

 On the LOth of the present month, I received a match box nearly full 

 of specimens of several species collected in his garden. Amongst 

 them were five fine specimens of M. vomitoria, and eleven of Eristalis 

 tenax. Oamaru is a pretty little seaport town in North Otago, 100 

 miles south of Ashburton. In a similar way I have lately received 

 two specimens of M. vomitoria from Mt. Somers, a village situated 

 near the base of the mountains, thirty miles inland from Ashburton. 

 Other non-entomological friends, residing in different districts in the 

 South Island, have sent me numbers of flies, but these are the only 

 localities so far that have yielded specimens of M. vomitoria. I have 

 recently received specimens from Danivirke, Hawke's Bay, thus 

 showing that the species is extending its area of distribution in the 

 North Island. 



The extremely rapid increase and dispersion of introduced insects, 

 and their effects on the indigenous species of the group to which they 

 belong, merits close attention. Although M. vomitoria is as plentiful 

 as Galliphora quadrimaculata and Sarcophaga Icsmica, there is not, at 

 the present time, any appreciable diminution in the numbers of these 

 two common native species. It is, however, too early to speculate on 

 the probable results of introduced Dipterous on the endemic Dipterous 

 fauna. The large and handsome Tahanus impar soon vanishes from 

 newly settled districts. Gomptosia hicolor, and the recently described 

 C. virida, Hudson, have increased somewhat in this district during the 

 last ten years. A week ago I spent a forenoon collecting Diptcra on 

 a large flowering plant of the introduced Buddlea glohosa. The 

 highly-scented, orange-coloured flowers are a great attraction to 

 Diptera and other insects, and have, for several years, enabled me to 

 obtain a good series of different species. It is very pleasant to watch 

 the larger Diptera chasing each other actively about the shrub, while 

 the smaller native species may be seen in a perpendicular position, 

 thrusting their heads down the short, narrow, staminal tubes of the 

 flowers to reach the nectary. Although there were about a dozen 

 species all busy at the flowers, M. vomitoria was much more numerous 

 than any other present. Last summer I observed them abundant on 

 several flowering plants of native Vericonce, and, later, on the flowers 

 of the introduced hybrid V. Andersoni. With few exceptions, the 

 species was common on nearly all flowering plants during the last two 



