566 



present its effects have been negligible, as also are those produced by 

 some of the cochineal insects from recent consignments. 



Apart from the bacterial disease now being carefully studied, the 

 most important enemy received seems to be Melitara prodenialis. 

 The South American Zophodia should have a similar effect. The 

 larvae of these moths bore into the joints and feed there. The Queens- 

 land prickly pears are readily attacked by these borers, which— like 

 all the other insects mentioned here— restrict themselves to cactaceous 

 plants. Until the hibernating larvae of Melitara breed, it will not be 

 possible to know whether the importation has been successful. 



The bugs [Chclinidca), weevils (Gersiaeckeria) and cochineal insects 

 all appear to be breeding satisfactorily. Though scavenging flies 

 emerged in large numbers from the Florida and Texan material, 

 nearly all have died, and none have bred. Extreme care was taken 

 in Texas and Florida to eliminate all parasitic or predatory insects 

 detrimental to the organisms that have been imported into Queensland. 

 The South American fungi have not responded well to the cultural 

 methods ; in Argentina they are very effective. 



In this attack on the prickly-pear pest the author is endeavouring 

 to utilise organisms acting in various ways : — (1) Insects that actually 

 eat the plant {e.g., moth-borers, weevils, etc.) ; (2) insects that suck 

 the juices, either weakening or poisoning the plant (cactus bugs, 

 cochineal insects) ; (3) insects that attack the fruit {e.g., certain midges, 

 Cecidoniyia {Itonida), Asphondylia, not yet imported) ; (4) insects, such 

 as scavenging flies, that continue destructive work such as is done by 

 those of the first group and passively assist the introduction of 

 saprophytic fungi and bacteria ; (5) actual disease-producing agents, 

 such as fungi and bacteria. 



Such of the organisms established in the laboratory as appear 

 unlikely to threaten economic plants will be studied in the field in 

 prickly-pear centres and then distributed if satisfactory. 



It is perhaps unwise to expect that the new arrivals will be so 

 destructive to the Queensland prickly pear as the Indian cochineal 

 insect has been to 0. monacantha, but it is hoped that they will be 

 sufficiently effective to leave only a remnant of the pest that can be 

 dealt with without difficulty. 



DoDD (A. p.). A new Grass Pest of the Atherton Tableland. — Queens- 

 land Agric. J I., Brisbane, xvi, no. 2, August 1921, pp. 79-81. 



During the drier months of 1920 (July to November) serious damage 

 was done to the pastures of the Atherton tableland by a Hepialid 

 moth, Oncopera mitocera, Turner. The other species of this genus, 

 0. intricata, is a grass-destroyer common in Victoria and Tasmania. 

 0. mitocera appears to be confined to north Queensland, and possibly 

 to the Cairns district. 



A brief description is given of the various stages. The moths are 

 on the wing in late March or early April. Early in October the larvae 

 were about two-thirds grown ; full-grown and pupating larvae and 

 pupae were found in the first week of March. No larvae and very few 

 pupae were seen in mid-April. It is therefore almost certain that the 

 life-cycle is completed in a year. 



The larva constructs a vertical tunnel in the soil from 5 to 16 inches 

 deep. In pastures, but not in the scrub, the tunnels are covered with 

 a mat of webbing and frass. The larva emerges at night to feed on 



