T. KiKK. — Displacement of Species in Neiu Zealand. 5 



Amongst introduced insects are numerous Coccidae, of 

 which there are upwards of twenty species, many of them 

 being highly injurious, the three most dangerous perhaps 

 being the fluted scale {leery a purcliasi, Mask.), which affects 

 many species of indigenous and cultivated trees and shrubs ; 

 the mussel scale {Mijtilaspis pomornm, Bouche), the great 

 pest of the apple, but also found on numerous shrubs and 

 trees, both introduced and indigenous ; and the black scale 

 {Lecaninni olece, Bern.), all of which are widely dispersed, and 

 may be found intermixed with the indigenous Dactylopius 

 gla2LGUs (Mask.), and other native forms, which have increased 

 to a large extent owing to the large supply of introduced plants 

 available for food, and possibly to the absence of enemies. In 

 the case of the Dactylopius, at least, this increase is occasion- 

 ally accompanied by a partial abandonment of the native 

 pltints on which it formerly subsisted. Thei'e does not appear 

 to be any instance of the replacement of a native scale- 

 insect by an introduced species. The number of naturalised 

 aphidian insects is even larger than that of the Coccidte ; but, 

 unlike the members of that group, they do not come into 

 competition with indigenous species, as the family can 

 scarcely be said to be represented in the indigenous fauna, a 

 single undescribed species of doubtful affinity being the only 

 form observed at present ; it is small, apparently rare, and seems 

 restricted in its choice of food to a purely herbaceous ground- 

 sel (ErecJitites prcnantlioidcs, DC). The introduced kinds, 

 however, have increased to a vast extent, and in many in- 

 stances infest different kinds of plants to those on which they 

 usually live in Europe. Amongst the most troublesome are 

 Aphis pruni (Reaum), on the plum; A. amygdali (Fonsc), on 

 the peach ; A. mali (Fabr.), chiefly on pome fruits; Siphono- 

 p>hora fragaricce (Koch), on the strawberry; and ScJiizoneura 

 lanigera (Hans.), on pome fruits: all of which are widely 

 distributed ; while Phylloxera vastatrix (Planch.) is only found 

 in the north. 



Thrips appear to be in course of displacement by intro- 

 duced species, but my knowledge of this group is insufficient 

 to allow of details being given on this occasion. 



Few New Zealand residents of the present day can form 

 any accurate idea of the injury and annoyance inflicted upon 

 the early settlers by the native flesh-fly, which was formerly 

 most abundant in all districts. A spade or other implement 

 used by a man with greasy hands would speedily become 

 fly-blown. Newly-cooked fresh meat could scarcely be trans- 

 ferred from the camp-oven to the table before it was attacked, 

 while blankets or woollen garments were speedily rendered 

 useless when exposed. But this troublesome pest has prac- 

 tically disappeared, having been displaced by the introduced 



