18 Transactions. — Miscellaneous. 



Injury caused by Insects. 



A small native beetle, which I have not been able to 

 identify, has greatly reduced many species of Cclmisia and 

 other tompositse by depositing its eggs on the disc florets, 

 where they quickly enter the larval state, and destroy the 

 carpel before it reaches maturity. The great increase of this 

 insect during recent years is doubtless caused by the frequent 

 burning of the surface vegetation, and consequent destruction 

 of the lizards and predatory insects which kept the beetle 

 in check. Several species of Diptera which are equally 

 destructive doubtless owe their rapid increase of late years to 

 the same cause. 



Displacement by Introduced Plants. 



In many instances a comparatively few species of natural- 

 ised plants have taken possession of sea-beaches, completely 

 displacing the original vegetation by their more vigorous 

 growth and their vast numbers — simply crowding it out by 

 depriving it of air and light, and to a large extent absorbing 

 its nourishment. This may be seen, for instance, south of 

 the Township of Kaikoura, where a broad stretch of land at 

 the water-margin is wholly given up to such weedy plants as 

 the common brome-grass (Brovms sterilis, L.), docks {Bunicx 

 obtusifolius, L., B. crisjms, L., &c.), fleabane (Erigeron cana- 

 densis, L.), catch-fly (Silcne anglica, L.), Yorkshire-fog {Holcus 

 lanatiis, L.), and others, perchance intermixed with one or 

 two native plants of similar habit. Here the displacement is 

 almost complete, the original littoral vegetation having been 

 driven to a few peculiarly favoured spots, where it maintains a 

 somewhat precarious existence. 



The displacement of the New Zealand flax {Fhormium 

 tenax, Forst.), the coarse sedge known as toe-toe- whatu- 

 manu {Cyperns ustulatns, A. Rich.), and the common fern 

 {Pteris esculenta, Forst.), by European grasses and clovers 

 is so striking that it has arrested the attention of the na- 

 tives ; and, indeed, it is calculated to attract the notice of 

 even a casual observer, for the indigenous species mentioned 

 are so robust that the mere idea of their being overcome in 

 the struggle for existence by such plants as clovers and grasses 

 seems almost absurd : but the fact remains. Seeds of rye- 

 grass, meadow-grass, white or red clover, &c., germinate by 

 the side of the coarse-growing toitoi, and gradually abstract 

 the moisture which it has been enjoying undisturbed ; the 

 growth of the sedge becomes less vigorous, while that of the 

 interlopers is more robust. The result would not be in doubt 

 were the plants now left undisturbed, but an overpowering 

 force comes to the help of the invaders- — the rich grass attracts 



