io STEWART MACDOUGALL—ON THE LIFE-HISTORY 
The day temperature of the orchid-house referred to was 
never below 60 degs. F., and the night temperature never below 
55 degs. F. The temperature of the house where my experiment 
took place was higher than this. 
Besides the species named above as plants in which my 
beetles bred, the following other orchids were used as food :— 
Dendrobium nobile. Cattleya sp. 
59 cariniferum. Phajus sp. 
” Wardianum. Oncidium sp. 
PREVENTIVE AND REMEDIAL MEASURES, 
Unfortunately in connection with this pest, there seems to be 
_every possible combination against the plant and in favour of 
Diaxenes dendrobtt :— 
The beetle breeds in a number of genera. 
Many genera can be used as food. 
The beetles, owing to their colour and their being night 
feeders, escape notice. 
The length of development from egg to imago is not excessive. 
The imagines have a fairly long life. 
From what I have seen of the work of this beetle, I have no 
hesitation in saying that Dzaxenes dendrobti is the very worst of 
orchid-pests, and yet, with reasonable care, successful war can be 
waged against it. 
I. Let all imported plants before being added to a collection 
be carefully gone over. Any brown discoloured pseudo- 
bulbs should be suspected and examined for the larva. 
Perfectly sound pseudo-bulbs have a firm feel to the 
fingers ; infested pseudo-bulbs “give” a little on being 
pressed. 
2. Owners or cultivators of orchids should keep a careful 
look-out for the work of the imago. Its damage is not 
to be mistaken for any other—how characteristic it is 
the figures show. Any found heetles should 
destroyed. They must be searched for, however, after 
nightfall with a lamp or lantern. 
3. That the larva has got to work may be known by a 
gradual discolouration down one side of the pseudo- 
