223 
The larvae, of the beetle Mcechidius ntgosus live in the thick bark of E. robustn, where they pupate. 
(Froggatt, op. cit. x, 331.) 
The soft young foliage of E. robusta is much frequented by many of the leaf-eating beetles such as 
Anoplognathus (several species) and the beautiful pale green Xylonychus eucalypti Boied.. which is often 
found feeding upon it in November and December. There is a large nut-like gall formed on the branchlets 
by the larvae of an undescribed gall-fly (Cynipidae) ; and the homopterous galls of the four-horned 
Brachyscelis (B. munita >Sch.) sometimes form great masses as big as a man's head upon the branches. 
Dac/ylopius eucalypti Mask., which was described by Maskell under the bark, was found by Froggatt 
burying itself in the young leaves and causing them to wither and become discoloured. Mr. Maskell records 
this fact from the former's notes in the Trans. N.Z. Inst., vol. xxv, p. 233, 1892. 
Mr. Froggatt has bred the beautiful wood-moth Charagia spltndens Scott, from a tree of Eucalyptus 
minima (Proc. Linn. Soc. N.8.W-, 2nd ser., ix, 382). " This species breeds annually, forming a thick felty 
bag all round the branch, and boring a hole several inches down the stem or branch, the larvae pupating 
about the middle of December, and the moth coming forth three or four weeks later." 
Galls. Insects on plants suggest galls, and there is a charmingly illustrated, 
Copious, general account of Galls in " Natural History of Plants" (Kerner and Oliver), 
ii, 527-554, from which the following notes (not, however, referring to Eucalyptus) have 
been taken : 
Certain members of the Arachnoidea, Diptera and Hymenoptera, which attack and penetrate 
the tissues of living plants and incite the formation of peculiar excrescences, arc known as gall-mites, gall- 
gnats, and gall-wasps. . . . 
It has been proposed recently to substitute the word cecidium for gall, and to distinguish the 
excrescences as myco-cecidia, nemato-cecidia, phyto-cecidia, diptero-cecidia, &c., according as they owe 
their origin to Fungi, Thread-worms (Nematodes), Gall-mites (Phytoptus), Gnats (Diptera), &c. 
The authors go on to say : " A systematic classification of this sort, on the lines of the classification 
of animals, might be of use to Zoologists, but to the Botanist its value is only secondary. He must, as in 
other similar oases, keep to morphology as the primary ground of classification, and has to arrange the 
structures according to their agreement in development. Moreover, in a general review, it is necessary 
to consider whether a whole group of plant-organs or one alone undergoes metamorphosis ; and the starting- 
point of the out-growth must also be ascertained, i.e., whether it is the foliage-leaves, floral-leaves, stems 
or root structures, which are the headquarters of the excrescence." 
When the gall originating as the nest or temporary habitation of a single, animal or colony of animals 
is limited to a single plant-organ it is said to be simple; if, on the other hand, several plant organs are 
concerned in its production, it is said to be compound. 
Simple galls may, for convenience of description, be divided into 
1. Felt galls. 
2. Mantle galls. 
3. Solid galls. 
The Felt galls are chiefly due to hypertrophied epidermal cells growing out into hairy coverings 
of various sorts and shapes ; Mantle and Solid galls, however, are rather more complicated. In both cases 
insects are present in swellings of various descriptions, but there is this essential distinction : the Mantle- 
gall is a hollow structure which, although it may arise in various ways and assume a multiplicity of forms, 
always has a portion of the surface of the affected organ for its lining in other words, it is a chamber 
formed by hypcrtrophied growth around the place occupied by the insect. In the Solid gall, on the other 
hand, some spot is pierced by an insect, and the eggs deposited in the tissues (not on the surface), the 
punctured spot forms a swelling with the larva inside, but the lining of the chamber is in no sense a portion 
or development of the original surface of the organ affected. Again, while in most Mantle galls the cavity 
of the gall is in open communication with the outside, and the insect can escape by this aperture (though 
this is not invariably the case), in the solid gall there is not such opening, and the insect has to bore its way 
out. Needless to say, of both these types there are numerous modifications, but they fall into the two 
classes (of Mantle and Solid galls) according to their mode of development. 
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