136 QUEENSLAND AGRICULTURAL JOURNAL. {1 Fes., 1902. 
legs are spined, but in a much less pronounced degree than occuys in the 
female insect. The feelers (antenne) are also almost straight, 13-jointed, and 
longer and narrower than are those in its case.- The eyes are black. The 
mandibles, or jaws, are less conspicuous than in the opposite sex. 
The contrast in habit and in colouration between the male and female 
insects, as is indicated by the foregoing descriptions, is very pronounced and is 
such as to readily suggest—as happened in the case of their first describers—that 
we have in them types of distinct species of insects. 
Hasirs. 
At what period in the growth of the cane-grub the parasite first attacks it 
has not been definitely ascertained. But there are grounds for concluding that 
this generally takes place when the latter has arrived at nearly its full size, but 
has not yet fabricated its subterranean cell perparatory to pupating. It is 
certain, however, that when assailed it is in many cases several inches beneath 
the surface. Whether the Dielis makes tentative explorations in the soil in 
quest of its prey or not has, moreover, not been discovered; but it is believed 
that nothing of the kind takes place. Having once decided where operations are 
to commence, after sailing with a swinging flight in a serpentine course amongst 
the cane plants at a short distance from the ground, and alighting 
now and again on or close above it, it quickly commences to dig, 
using its formidable scoop-like jaws as the principal agents in accom- 
plishing this purpose, although bringing into operation as auxiliary 
instruments its spine-bearing front legs also. The particles of soil freed 
by these from their surroundings are quickly transferred to the curious ridged 
plates that (as mentioned in the account given above of the female insect) 
occur upon the expanded tibial joints of the hind legs, and are then rapidly and 
forcibly ejected backwards. During this work the insect constantly crawls 
upwards towards the mouth of its burrow, again and again rejecting in doing so 
soil-fragments. This process of excavation is rapidly executed, with the result 
that if the soil be friable the industrious insect is soon hidden from view. It 
is, however, by no means essential for its work that the earth through which 
it tunnels its way be of a loose texture. It must be admitted, however, that 
where the writer found beetle-grubs to be parasitised by it, in greatest amount, 
the soil frequented was of an alluvial open nature. Having at length found a 
grub, it deposits a single egg and this it fastens with some sticky substance 
generally just behind the origin of the third pair of legs. Whether this act on 
its part is preceded by an administration of poison by means of its sting has not 
been observed. The comparative inactivity that the grub henceforth exhibits 
may be attributable, however, to the fact that this event transpires.* 
As more than one egg has been found within the body of a single female 
Dielis, it is probable that the laborious work of hunting for beetle grubs in the 
soil whereon to oviposit is at least once repeated. 
The egg, once placed in the situation named, evidently soon hatches, and 
gives rise to a footless maggot-like larva, but one in which the individual body 
segments are discernible, and that is rounded at the hind extremity, but tapers 
gradually towards. the head; this part of the body being bent and directed back- 
wards both when the insect is attached to its host as well as when ultimately 
it has become free. 
Immediately on hatching this larva gnaws a hole or rent at the exact spot 
where it is born, through the skin of the beetle-grub, and inserting its head as 
* Passerini states that the European Scolia flavifrons attacks its victim—the Oryctes nascicornis 
grub—at a time in the development of the latter when this has arrived at that period of 
Inactivity when internal changes are being undergone that convert it from a larva to a nymph, 
and thatit is accordingly possible that the mother Scolia does not require to sting the beetle- 
grub in order to stupify it. Fabre, on the other hand, according to D. Sharp, has found that a 
congeneric species, the Scolia bifasciata, of Europe also, prior to attaching its egg to the grub of 
Cetonia beetles, stings the latter in a definite position ‘‘the line of demarcation between the pro- 
and mesothorax on the middle line of the ventral surface,” and so destroys the sensibility of the 
grub, without meanwhile determining its continued existence until the food requirements of the 
young parasite—in the matter of living grub-tissue—are fully satisfied. [Sharp l.c. p. 98-99.] 
