356 DINODERUS MINUTUS. 

Description, Life-Htstory. 
Although the results of the work of the bamboosbeetle are 
well-known, the real author of the depredations is far from 
being a well-recognised enemy owing both to its small size and 
to its secretive habits. The damage is committed by a tiny 
beetle (Plate XX, fig. 85 shows a dorsal and side view of this 
beetle) and its grubs which are just of slightly smaller diameter 
than the holes with which the bamboos are seen to be riddled. 
The beetle, which has a black head and thorax and reddish- 
coloured, shining wing covers, bores its way into the bamboo and 
lays its eggs in the interior, each beetle laying about 20. From 
these eggs small, white, roundish dots of grubs (see fig. 8) issue 
within a few days of their being deposited. These tiny larvee 
burrow up and down in the interior of the bamboo and reduce its 
structure to powder. About four weeks are spent in this stage, 
and the grubs then enlarge the ends of their burrows and change 
to pupe (fig. 8a) which, after some eight days or so, turn into the 
beetles. On becoming mature the beetles bore their way out 
of the bamboos and thus add further to the tunnels already made 
in them. On emergence the insects fly off to attack fresh bam- 
boos, or they may bore into the one in which they have them- 
selves matured. Thereare thus three separate forms of attack :— 
(a) The female beetle bores into the interior of the bam- 
boo and lays itseggs there. This is the first attack 
on the bamboo. 
(2) From the eggs hatch out little grubs which feed upon 
the wood of the interior of the bamboo, and thus 
undermine its strength. 
(c) The beetles on maturing from the grubs bore their 
way out of the bamboo. 
It used to be thought that each of the shot-borers made its 
way out by a separate tunnel, driven direct from the place where 
the grub had pupated to the outside. This is not, however, the 
case, as the matured beetles appear to issue either all from the 
same exit-hole or from one or two only, these being often the 
former entrance-hoies of the mother beetles, which are consider- 
ably enlarged. Beetles of the new generation appear to also 
