468 . QUEENSLAND AGRICULTURAL JOURNAL. [1 Dzc., 1897. 
honey bees conveniently near to his orchard, for thereby the partial infertility of his 
trees will be often avoided. Whilst on this topic, allusion might be made to the 
useful work accomplished in New Zealand by the Bumble Bees (Bombus) in 
fertilising the red clover. 
Crass 2 comprises, as has been already stated—(1) Predatory insects or such 
as. immediately prey upon noxious members of their class; and (2) Parasitic insects 
that deposit their eggs on or within these, that then serve as food for their resulting 
young. Both predatory and parasitic insects are numerously represented in Australia 
both by varieties and individuals; and were even typical specimens of those that occur 
in. Queensland to be brought together, the collection would occupy some scores of 
cabinet-drawers. The Carabida, a single predaceous family of one order of insects— 
viz., beetles —of Australia contained in the collection of the Government Entomologist 
of Australia, alone fill many large drawers. 
Predaceous Insects.—¥rom the foregoing remarks it may be inferred that these 
are far too numerous to admit of even the principal genera being enumerated, much 
less described. They embrace representatives of all the different orders. _Amongst 
the Coleoptera are the Tiger Beetles; the Carabide; the Flower Beetles, or Clerida ; 
the Brenthidw; the Soft-Winged Beetles (Malacodermide); and last, but not least, the 
Coccinellidew, or Lady Birds—which, with the exception of the species belonging to the 
genus Ff. pilachna, are almost exclusively predatory beetles. Caterpillars, ground- 
feeding grubs, wood-borers, aphids or plant lice, and Scale Insects amongst other pests 
form the food of this host. 
The Hymenoptera is again an order of insects exceedingly rich in predaceous 
members of this class. One need only mention in illustration: Ants, including the 
entire family Poneneridw and the species of the genera Aeophylla and Myrmecia ; the 
wingless females of the Mutillia and Thynnide, the large yellow and black and other 
coloured Scoliadw; the large silver and black and other Sphegide ; the Fly-eating 
Sand Wasps (Bembecide), the Hunting Wasps (Pompilide), the Solitary Vespide, 
including the Mason Wasps (umenes), &c.; the Social Vespide, including Polistes, 
&e. All kinds of insect pests fall a prey to these.* 
Parasitic Insects —These that are almost exclusively members of two orders of 
insects—viz., Coleoptera (Beetles) and Diptera (Two-winged Flies)—are eyen more 
numerous than the predatory forms last considered. Almost every plant-eating insect 
—even the smallest of them—will be found to have at least one parasite associated 
with it, and some indeed several. The mere description of the different parasitic 
insects of Australia would alone fill several volumes of letter-press. The Common 
Soft Scale (Lecanium hesperidum) has no less than six different kinds of minute 
Hymenoptera parasites within it (F. M. Webster); the Red Scale (Aspidiotus coccineus). 
has also a like number (L. O. Howard). Another Soft Scale (Lecanium Fletchert) 
is also found to have six true parasites. The following facts regarding this insect and 
its enemies of this description, will illustrate the important part played by parasitic 
insects :-—Four little twigs of Arbor vite gathered by Dr. James Fletcher, of Ottawa, 
were found to be infested with no less than eighty specimens* of the Lecanium in 
question ; but of this eighty, all but five were parasitised, the parasites numbering 
no less than eighty, and comprising representatives of six different species belonging 
to five distinct genera of Hymenoptera.t Again, in the case of a single caterpillar, 
the White Marked Tussock Moth (Orgyia leucostigma, S. § A.), that 1s represented 
by a co-gencric caterpillar pest in Queensland, L. O. Howard has found no less than 
twenty-one different kinds of true parasites, fifteen of which were Hymenoptera 
and six Diptera.t These illustrations are afforded by occurrences transpiring else- 
where, by reason of the fact that little attention as yet has been given to the subject 
of insect parasitism in this country; no one, except the present writer, having as yet 
described any of our parasitic Hymenoptera, though more than one species has, it is 
true, been figured. ‘“ Whenever a plant-feeding species from some cause or from 
some combination of causes, transcends its normal abundance to any great extent, there 
is always a great multiplication of its natural enemies, and this multiplication is 
usually so great as to reduce the species to a point even below its normal. Exceptions 
to this rule are seen with especially Pe atetall species, that through the possession of 
some distasteful or repugnant quality, have no predatory or parasitic enemies. Even 
in such cases, disease steps in and fills the want’ (L. O. Howard). It may be 
*The writer, in continuation, proceeded to refer to remaining orders of insects—Neuroptera, 
Hemiptera, Orthoptera, Diptera, and Lepidoptera—mentioning, in the case of each, numerous 
predaceous insects and the special harmful species which they served to hold in check.—Kd, 
Proceedings A.F.C. 
+ 
Ae? L. O. Howard. Some Mixed Results of the Work of the Divis, of Entom., pp. 62-63, 
/ iI, OQ. Howard. A Study of Parasitism, 1897, p. 7. 
