TACHINIDAE OF AUSTRALIA 167 
positively to provide hosts, and these same orders provide the hosts for the 
overwhelming majority of world forms: the Lepidoptera and Coleoptera, as elsewhere, 
provide the greatest number of different host species, and the Orthoptera, 
Hemiptera-Heteroptera and Hymenoptera are regularly parasitized by particular 
groups of Australian tachinids; a few species of stick-insects (Phasmatodea) and 
mantids (Mantodea) also provide hosts. The rather well developed fauna of 
Embioptera in Australia is not known to have tachinid parasites, but may be found 
to do so (as the tachinid genus Rossimyiops Mesnil is parasitic on an embiopteran 
in South Africa). There is one remarkable record of an Australian tachinid 
parasitizing adult Tabanidae (Diptera) (Spratt & Wolf, 1972). 
Tachinids are presumed to play an important role in the natural regulation 
of the numbers of their hosts, but this is difficult to quantify. In Australia many 
of the economically important insect pests are attacked by tachinid parasites, 
and some parasite species are regularly reared in numbers from their host pest 
species. Particular tachinid groups may be confined to particular host groups 
(e.g. the Phasiinae only attack Hemiptera and the Acemyini only attack 
Orthoptera) but true host-specificity in the sense of a single species of parasite 
confined to a single host-species is apparently rare in the Australian fauna (and 
the apparent instances where host-specificity occurs are probably mainly due to 
insufficient knowledge). Certainly several of the main injurious pests are attacked 
by several species of tachinid, and many of the tachinids attacking these pests 
also have other hosts (as is evident from the accompanying parasite-host and 
host-parasite lists). 
The range of economically important Australian insect pests that are attacked 
by Tachinidae is very diverse, and includes pests of agricultural crops (sugar-cane, 
cotton, maize, cucurbits) and many serious defoliators of forest timbers. Some 
of the most important pests, with their parasite-groups, are: the cotton bollworm 
(Heliothis armigera), the army-worm (Persectania, Pseudaletia, Spodoptera spp.) 
and cutworm (Agvotis) pests of cotton and other crops that are attacked by many 
species of Tachininae and Goniinae; the sugar-cane borer weevil (Rhabdoscelus 
obscurus) attacked by Lixophaga sphenophori; the white-grub larvae of melolonthine 
beetles, especially the sugar-cane white-grub (Dermolepida albohirta) of the 
Queensland canefields, attacked by species of Palpostoma and of Rutiliini; the 
introduced scarabaeid beetle Heteronychus arator, a pest of maize in New South 
Wales, that is attacked by species of Palpostoma; the chrysomelid beetle 
Aulacophora hilaris that destroys the foliage and flowers of cucurbitaceous crops, 
attacked by a species of Blondeliini; the cotton-stainer bug (Dysdercus sidae) of 
Queensland, attacked by species of Phasiinae; the pergid sawfly defoliators of 
Eucalyptus, attacked by several species of the Anagonia-Froggattimyia complex 
(Blondeliini); the chrysomelid beetle Pavopsis atomaria, a pest of Eucalyptus, 
attacked by several species of Blondeliini; and the stick-insect Didymuria violescens, 
a serious defoliator of Eucalyptus in New South Wales, that is attacked by an 
undescribed tachinid of very uncertain systematic position. 
Despite the diversity of economically important insect pests, and the extent 
of work undertaken on them by Australian departments of agriculture and 
