,6 FAUNE ENTOMOLOGIQUE DE l'aUSTRALIE 



shellac, othcrs are liglitcr, or darker, and tlic rows of dorsal spincs or teeth differ in length, 

 shapc, numbcrs, and in manner of disposition, but thc main and most readily perceived diffé- 

 rence is in the head-piece or beak, which breaks or pushes out the operculum; it may be short 

 and biunt, rathrr broad, or rathcr fuie and sharp, ail différent, but constant in each species. 



To bc at al! successful with the moths each tree or branch with a pupa therein must be 

 fellcd, and the block with its inmate eut off, which is often a pièce weighing 70 or 80 Ibs, or 

 occasionally more, then thèse must be carried home and kept under observation. In hot dry 

 periods many pupae cannot force out the operculum, so die in the block, then many hâve bcen 

 victimised by ichneumons, or crippied by the shock of cutting and falling of the trees. More 

 than one half of .V. phaeosoma Turner, which I had at Port-Darwin, died m the wood, and at 

 Icast one ihird of Boisduvalt resuit in failures. 



AU species do not work upwards in the tree, several work both ways, and two or three 

 others downward only; ail do not construct a regular operculum, -Y. liturata and another spin 

 a broad felt-like ring, meeting (but only slightly closed) in the centre; this is so thick and tough 

 that the pupa must possess great strength to force its way through. A', cucalyptii is almost 

 wholl)- confined to the roots, and often before pupation has to eut a passage through several 

 inches of earth to the surface, this is neatly lined with web and fragments of bitten bark and 

 wood — I hâve met with one of thèse tubes 5 or 6 inches in length. I do not remember that 

 this moth ever came out at the base of a tree, always from a root. Tenebrifer may came from 

 eilluT, l)ut iisually, iT nol always, whcre ihcre is no earth over the wood. There are several forms 

 of X. li/nriitii, pcrhaps thcy will m time be separated into species; one form émerges as early 

 as 10 or 1 1 am, another as late as 5 or 6 p. m. But the majonty of species émerge between 

 1 1 a. m. to 3 p. m., and, as a rule, the hotter and drier the day the earlier the émergence. 



Some species of caterpillars are pearly whitc, being yellowish when young, others arc richly 

 reddish when young, becoming paler until at maturity they hâve changed into a dirty pinkish 

 white. A'. Boistlindlli and its allies are banded with white and dark purple when young, chan- 

 ging with âge to whitc witli |)alc purplish bands. 



What is particularly interesting in ail thèse insects is that they possess the power of pupating 

 at any time after having attained little more than one third of their growth if their food supply 

 fails; time after time hâve I proved this, often having moths only 2 1/2 inches in expanse, 

 whereas, had they been left fyr their full period, thcy would hâve been 6 or 7 inches across. 

 Doubtlcss this is a provision agariKt extinction, for so many trees are killed by lire and drought, 

 and branches and young trees are kif}ed sometimes by the insects themselves, or are snapped off 

 by violent winds. Larvae often eat sonae distance around their bores, and the trees, being 

 weakened, are liable to break in a gale or die. from such other causes as mentioned. Once in 

 Brisbane district I found several branches and young trees, containing caterpillars of Zeiiseridœ, 

 which had been snapped off during a severe thunderstorm ; sawing off the ends and taking them 

 home the insects therein soon pupated, and in due course the moths emerged, ail being very 

 small. 



