1 Fes., 1902.] QUEENSLAND AGRICULTURAL JOURNAL. 1338 
Entomology. 
A PARASITE OF SUGAR-CANE BEETLE GRUBS 
(Dielis formosus, Guérin). 
By HENRY TRYON, Entomologist and V. Pathologist. 
(Pate IX.) 
InrTRoDUCTORY. 
In connection with some of the incidents relating to the occurrence of the 
larve of more than one of the scarabieid beetles that live in such pronounced 
injurious relation with the sugar-cane in one district or another throughout the 
coastal agricultural lands of Queensland, the belief has been engendered that 
these pernicious insects have been at certain times and in special localities 
decimated or partially subdued by some natural agency that has spontaneously 
arisen, and that has consisted in the counteracting presence of disease or of 
parasitic fungus- or parasitic animal- organism. 
As bearing on this experience, may be mentioned the almost complete dis- 
appearance, until a recent date, of the “grubs,” after great destruction had been 
experienced from their depredations, throughout considerable areas of both 
the Hambledon Plantation, Cairns, and the Goondi Plantation, Johnstone 
River—not to allude to other apparently illustrative examples of it also. 
Tn some cases, it is true, this has followed—as at Hambledon—the active 
and vigorous prosecution of methods of repression, exercised with great skill 
and judgment ; but, even where this has happened, the subsequent absence of 
the cane-destroying scarabeid larve was an event of greater importance than 
would be the one that might have been expected to follow as a result of their 
application. 
That the “cane grubs” are victimised in Queensland by disease and also 
by fungus and insect parasites has long since been announced by the writer 
(vid. “ Grub Pest of Sugar-cane in the Mackay District,” pp. 35-37, Brisbane, 
1896). ‘Ihe purpose, however, of this note is not to dwell generally upon this 
fact, but to call attention to a special natural enemy, whose existence and 
service in this capacity have both been hitherto overlooked, notwithstanding it 
may have proved highly efficacious in some instances in accomplishing the 
result to which allusion is made. 
This victimiser of the cane grub is an insect, belonging to the class 
Hymenoptera and to the family Scoliade, and named WDielis formosus, 
Guérin. 
Hisrorrca.* 
The male insectwas described by Fabricius as long since as 1793 (vid. “ Entomologia 
Systematica,” p. 356) under the title Srolia septemcincta, Fabry. Forty-four years 
subsequent to this the French naturalist Guérin made known to the scientific world 
(vid. Voyage de la Coquille. IT. p. 252, 1838) the opposite sex, bestowing upon it the 
name Scolta formosa, Guérin, but without the suggestion, that he was dealing with 
the identical species to that to which Fabricius’ account related, being given expression 
to. 
The type of S. septemcincta, Fabr., was derived from New Holland, and was 
probably obtained during Captain Cook’s expedition, and Guérin’s insect was derived 
from New Caledonia. 
The specific distinctness between the two insects was maintained by F. Smith 
(vid. Catalogue of the Hymenopterous Insects of the British Museum, III. p. 105, 
1855). Henri de Sanssure and J. Sichel (vid. Catalogus Specierum Generis Scolia, 
* Information of a more or less technical character such as is the subjoined is printed in 
smaller type than is the memoir in general.—Zd. 
