189 
XXX.—ADDITIONS TO THE WILD FAUNA AND 
FLORA OF THE ROYAL BOTANIC GARDENS, 
Ws: ZV1 g 
Bark BEETLES: (COLEOPTERA). 
W. Datirmore and J. W. Munro. 
Phloeosinus thujae, Perris (The Thuya Bark Beetle). The 
abnormal drought of 1921 seriously affected the health of many 
trees at Kew and those that were unduly weakened have been 
carefully watched during the present year for signs of improved 
health or further deterioration. 
Amongst the enfeebled trees were two specimens, at least 
40 to 50 years old, of Thuya orientalis near the Cumberland gate. 
In the autumn of 1921 they had an unhealthy appearance and 
_ the winter rains effected little improvement. During late spring 
a number of branches died and by the end of June the bark had 
begun to separate from the wood. On examination the presence 
of a bark beetle was detected. This was submitted to Dr. J. W. 
Munro, Entomologist to the Forestry Commission, who identified 
it as Phloeosinus thujae, Perris, a beetle that had not hitherto 
been found in Britain although it is known to occur on the 
Continent on species of Thuya, Cupressus, and Sequoia, and 
also on Juniperus communis and J. Sabina, attacking sound 
healthy trees, its attack beginning on the uppermost twigs and 
spreading downwards. Towards the end of July the beetle 
was found on Cupressus pisifera in another part of the gardens, 
half a mile from the original locality. 
Dr. Munro has kindly contributed the following particulars 
respecting this beetle together with highly magnified drawings 
of the insect and its main and secondary galleries. 
* Phloeosinus thujae belongs to the Hylesininae group of the 
bark beetles and is allied to the genus Hylesinus or ash-bark 
beetles. It is very dark brown or almost black in colour, about 
z's in. long. and differs from the ash-bark beetles in several 
important characters, of which, the absence of tubercles on the 
thorax, the deeply indented margin of the eyes, and the structure 
of the antennal club are the chief. 
“The brood galleries of Phlocosinus are typical for the genus. 
Like those of the ash-bark beetles the mother galleries are two- 
armed but unlike these last they are cut parallel to the stem axis 
and not across it. 
“Tt is at present difficult to determine whence these beetles 
came to Kew. They may have been imported on Thuya or they 
may yet prove to be indigenous in England. The first surmise 
is probably the correct one.” ee 
However interesting the discovery of an injurious insect ie 
to Britain may be to the entomologist it is disquieting to t ; 
cultivator and emphasises the danger of importing insect anc 
