1918.] The N.Z. Journal of Science and Technology. 133 
very like our native tits, and might possibly be successfully introduced 
to take the place of our native species in the northern parts of the country 
where the latter have now disappeared. The Australian wagtail would 
also be well worth having; and the magnificent lyre-bird of Australia, 
now threatened with extinction, might be preserved in one of our island 
sanctuaries, and, if it increased, could then be established on the mainland. 
Reciprocal action of a similar kind with Australia might be the means of 
preserving some of our native species from extinction. The African bee- 
eaters, sunbirds, and kingfishers, and the northern woodpeckers, are also 
groups that would yield many species worth consideration. 
Of mammals, the beaver calls first for attention, and would be a 
valuable addition to our assets on account of its fur if it could be esta¬ 
blished in South Westland. Some of the squirrels also would be useful in 
the same way, but care would have to be taken in the selection of these. 
There is abundant room for the koala, or Australian native bear, one of 
the gentlest and daintiest of animals, in our eucalyptus plantations, and 
it might be thus saved from its now threatened extinction. There is 
much to be said also in favour of the despised mole, which might control 
the grass-grub and would improve many of our soils, but it would have to 
be first experimented with in light volcanic soils, in which alone it might 
make trouble. 
The little green tree-frogs of southern Europe should thrive in New 
Zealand, and would be useful in our swamps, while the English toad 
would be invaluable to gardeners. The beautiful little flower - haunting 
chameleons of South Africa would be a useful addition to our fauna, and 
should do well in our northern gardens. 
It is when we turn to the insects, however, that the widest field is 
opened before us. None but a naturalist can realize how vast is the part 
played by the solitary Hymenoptera in keeping other forms of insect-life 
in check. Amongst our native wasps are two species very commonly 
found along river-banks or sandhills on the coast. The larger of these 
two provisions its nest with various species of Blattidae, including the Maori 
bug, which its young uses when half-grown. This group of insects is 
highly specialized, confining its attention to one species of prey only. 
The majority of our native wasps, however, live during larval stages as 
internal parasites; and doubtless many exotic species of both groups could 
be profitably introduced to deal with certain of our agricultural and 
garden pests. 
There are many other insects which would be useful in checking the 
spread of certain of our weeds, such as the cinnabar moth of Europe, 
which in its larval stages feed on the flower-heads and seeds of the ragwort. 
Another is the clearwing moth, Sesia chrysidiformis, of which the larvae 
bore into the stems of the common dock. 
It would add much to the beauty of lane and countryside if we could 
add a number of the gorgeous butterflies of the world to our very scanty 
number of these insects. Most of them are absolutely harmless, and some 
are positively useful, apart from the part all play in the fertilization of 
flowers. As a start I would suggest the following :— 
Vanessa antiope, of Europe, Asia, and America, feeding on willow. 
Vanessa io, of Europe and Asia, feeding on nettle. 
Thecla rubi, of Europe, feeding on blackberry. 
Thecla quercus, of Europe and Asia, feeding on oak. 
Limenitis populi, of Europe, feeding on poplar. 
Papilio sarpedon, of Australia and Asia, feeding on camphor-laurel. 
