ORCHIDS : HOW TO GROW THEM SUCCESSFULLY. 47 



about an inch high, as it becomes abnormally thick at the base and 

 tapers somewhat more to a point than is usual, the growth making but 

 little progress. The only method of exterminating this pest is to cut 

 out the infested growth, in the centre of which the young grub will be 

 found in a more or less advanced stage. If destroyed in this way an 

 effectual stop to their breeding is attained and much harm to the plants 

 prevented; but, should an infested growth be overlooked and the insect 

 come to maturity, a great amount of damage may be done for another 

 year. Luckily this insect is not very general, but it is always best to be 

 on the alert when buying plants. 



THE DENDROBIUM BEETLE (Xyleborus perforans) is of small size, 

 but quite large enough to be capable of a great amount of mischief if 

 not promptly checked, and should it get a foothold on the bulbs, as it 

 often does in the Dcndrobiums from the Torres Straits, such as D. 

 Phalsenopsis, D. P. Schroderianum, D. bigibbum, also D. Dalhousieanum 

 and D. formosum, it apparently has a liking for, but it does not 

 confine itself to these species. The presence of the insect is indicated 

 by the small cleanly bored holes in the pseudobulb, both new and old, 

 resembling the small holes found in old worm-eaten furniture ; should 

 these holes escape notice the leaves soon assume a yellowish appearance 

 and the pseudobulbs begin shrivelling about an inch below the holes. 

 If the pseudobulb is cut open a nest in a small cavity will be found 

 containing one or more of the beetles, and the surrounding tissues will 

 be in a state of decay It is an open question whether the holes are 

 first pierced by the adult beetle an insect nearly the size of and 

 resembling an ant and the larvae deposited therein, or whether they 

 are hatched in the pseudobulb and afterwards eat their way out of it, as 

 is the case with the Caftleya fly. This enemy may soon be stamped out 

 if proper and timely precautions are taken. I advise an examination of 

 the plants occasionally, and, if any traces of the beetle are found, to cut 

 away that portion of the pseudobulb and burn it ; in fact, should the 

 plant be found to be badly infested, burn it altogether, and give the 

 remaining plants a dressing of some insecticide. 



RED SPIDER. This insect pest is most troublesome, and on Dendro- 

 biums more than any other Orchids ; when plants are attacked by them 

 and arc unnoticed, serious results may follow, as they greatly reduce the 

 vitality of the plants. They usually attack the under surface of the 

 young tender foliage, and their presence can be detected by the leaves 

 showing a whitish appearance on the upper as well as the under 

 surface, which becomes more and more plainly visible as the insects 

 increase, which they do very rapidly, causing the leaves to curl and dry 

 up and probably fall off, almost completely arresting the further 

 progress of any growth in course of formation, and greatly interfering 

 with or destroying any prospects of flowering the next season. On the 

 first appearance of this insect, immediate steps should be taken for its 



