^^l^'''\ Excifvsiou from Croydon to Belgrave. 151 



tops of some eucalypts, and, although October is the best 

 month for this species, no other specimen was seen. While 

 traversing the track to Sherbrooke Falls I noticed that some 

 of the young leaves on the small Sassafras trees had l)een 

 partiall}^ eaten, probably by the larvae of the handsome Papilio 

 macleayanits. which appears on the wing during December- 

 February. Some of the young branches of the Native Musk- 

 tree also bore partly-eaten leaves, which may have been done 

 by the larv^ of Miletus hecalins, but, as this species is rather 

 local in its occurrence, the damage may have been caused by 

 the larvae of some moth. Had the day been fine and warm, 

 at least a dozen species of butterflies should have been met 

 with. — A. N. Burns." 



Any member of the Club who desires to introduce a friend 

 to the forest scenery of our State cannot do better than take 

 this outing, but, if considered too arduous, take the shorter 

 one from Belgrave to the Sherbrooke Falls, the gorge in which 

 they are situated being a splendid example of a fern gully and 

 its accompanying vegetation of huge gums, etc., concentrated 

 in a limited area. — F. Pitcher. 



UPSETTING THE BALANCE OF NATURE. 

 By H. W. Davey, F.E.S. 



{Read before the Field Naturalists' Club of Victoria, gth Oct., 19 16.) 



It is a matter for regret that the native Blackfish is rapidly 

 disappearing from our streams, where formerly it was so 

 plentiful ; and this in spite of the recent action taken by the 

 Fisheries Department in again raising the size at which this 

 hsh may be taken. The extinction of the Blackfish in the near 

 future seems certain, owing to the great mistake made in 

 introducing to this country the Common Perch, Perca fluviatilis, 

 which is one of the most voracious of fishes. 



It appears to be a natural law that an introduced species 

 displaces the indigenous kinds. In Australia we have numerous 

 examples of this, among which we see the white man ousting 

 the aboriginal. The fox and dingo are animals closely allied 

 to each other, yet the latter is rapidly decreasing in numbers, 

 while the fox becomes more numerous — this to an alarming 

 extent. He destroys many of our birds, among which the 

 Lyre-bird is a great sufferer. Other noteworthy examples of 

 the adaptability of importations to their new environment are 

 the rabbit and hare, while, on the other hand, our marsupials 

 are disappearing rapidlj^ Starlings are increasing, and will 

 become a serious menace to agriculture when they overtake 



