DUOMITUS LEUCONOTUS, Walker. 431 

The above figures show the very great variation in size to 
be found in both sexes. 
Life-History. 
The moths appear on the wing in the latter half of Septeme 
ber, and are to be found during the remainder of that 
month and on up to about the third week in October. They 
are extremely sluggish during the daytime, but are powerful 
fliers at night. In the day they are to be found clinging to the 
bark of trees which their general colouration greatly resembles, 
thus serving to protect them from the attacks of enemies. 
The male lives but a few days and dies after pairing with the 
female. The latter lays her eggs, which are small, yellowish 
and deposited in irregular-shaped masses stuck together with 
some siccable material upon the bark of trees, She dies as 
soon as she has finished ovipositing. Examination of attacked 
trees has shown that these eggs are laid anywhere upon the 
woody parts of the tree, and that the young larve on hatching 
out bore straight through the bark to the sapw ood and feed in 
this for a time, subsequently going into the hard wood of the 
stem or branch. The mortality amongst the young larva must 
be very high, since it would be quite impossible for any one tree 
to support the large number of larva the eggs of a single moth 
give rise to, it being remembered that almost the whole of this 
stage is passed feeding in the wood. The larve almost certainly 
spends not less than two years feeding in the wood of the tree. 
The evidence for this assertion was found in the case of a tree 
which had practically been killed by the insects. Mature pupz 
and moths were taken from this tree and also two half-grown 
(or less) larvae. Since the moths only issue in September 
October it is evident that these larve hatched from eggs laid at 
the very latest in the year before. 
The larva bores in an irregular manner in the wood, the 
tunnel having apparently no regular or definite direction, The 
tunnel increases in diameter with the growth of the grub, 
finally measuring over half-an-inch across, It is packed with 
the wood sawdust and excreta of the larva. When full-grown 
the larva carries its tunnel to the outside, boring a hole through 
